Principles and Practice of Sleep Medicine Third Edition (2000) Kryger MH, Roth T, Dement WC (Eds) W.B. Saunders Company Dreaming Disorders Tore A. Nielsen Antonio Zadra

Becausemost dreaming disturbancesinvolve a per- tive reactions to more basic pathophysiological factors, turbation of emotional expressionduring sleep, their rather than signs of a pathological disorder per se. As study may help clarify the role of emotion in dream the pathophysiologies of dream disturbances are still formation, dream function, and sleep mechanisms. only poorly understood, in this chapter we use the Physiological evidence for emotional activity during terms dretlmdisturbance and disturbed dreamingin a neu- rapid eye movement (REM) sleepis substantial.Auto- tral sense with respect to this question of etiology. nomic system variability increasesmarkedly in con- junction with central phasic activation.1as seen espe- cially in measures of cardiac function. 2.:Srespiration. 4 IDIOPATHIC NIGHTMARES and skin and muscle sympathetic nerve activity." 6 Historical Aspects Brain imaging, too, demonstratesincreases in meta- bolic activity in limbic and paralimbic regions during AlthouJdt the most prevalent form. of dream distur- REM sleep (e.g.,see references 7, 8), activity similar to bance is the idiopathic nightmare, its cause and psy- that seenduring strong emotion in the waking state.' chopathology remain largely unstudied. The Diagnostic Thesedramatic autonomic fluctuations globally paral- and Statistical Manual of Mental Disorders,Fourth Edition lel dreamed emotional activity, which is detectable (DSM-IV)20 criteria for nightmare disorder (Table 66-1) throughout most dreaming when appropriate probes have not changed substantially since the disorder was are employed.1OMost dreamed emotion is negative,l1 described as dreamanxiety disorder in the third, revised primarily fearful,10 and it may conform to a "surge- (DSM-ill-R) and as dream anxiety attack in third (DSM- like" structurewithin REM episodes.U Isomorphic rela- ill) editions. This is due, in part, to the fact that little tionships between physiological and subjective attri- new basic or clinical information about idiopathic butes of dreamed emotions have been reported (e.g., nightmares has been published since the initial studies see references13, 14) but are still poorly understood. of Fisher et al.21and the detailed clinical analyses by Nevertheless,many theorists interpret the various pe- Hartmann. zz ripheral manifestationsof phasicponto-geniculo-occip- The widely accepteddefinition of a nightmareis a ita! (pGO) activity as indicative of dream-relatedaf- frightening dream that awakensthe sleeper,but not all fective activity.12.15. 16 researchersadopt the "awakening" criterion. Some23 Emotional processesduring wakefulness are also argue that disturbing dreams that awaken merit the implicated in dream disturbances.For the most com- designation nightmare, whereas those that do not mon disturbances,such as nightmares,dreamed emo- should be labeled "bad dreams;" whether the person tion becomes unbearably intense and provokes an awakens is presumably an indirect measure of the awakening; this may lead to further distress which dream's severity. However, the awakening criterion continuesto influencewaking behavior and mood and may be an overly conservative estimate of severity. may even impair subsequentsleep. Perturbation of First, amongvarious psychosomaticpatients, even the dream-relatedemotion may thus lead to a cycle of most macabreand threateningdreams do not necessar- sleep disruption and avoidance,insomnia, 17 and psy- ily produce awakenings.24.25 Second,fewer than one chologicaldistress. Ie This often leads the individual to fourth of chronic nightmare patients report" always" seektreatment. awakening from their nightmares, and these do not However, causal relationships between emotion, correlatewith either nightmare intensity or psychologi- dreaming,and other associatedSYmptoms are not well cal distress.i1Third, among subjectswith both night- understood.In some instances(e.g., nightmare disor- mares and bad dreams, approximately 45% of bad der), emotional disruption may affect primarily sleep- dreams have emotional intensities equal to or ex- relatedprocesses-in which casethe dreaming process ceeding those of the average nightmare.:16Similarly, itself might be consideredpathological in somesense.19 many researchers define nightmares as disturbing However, the widespread belief in dreaming as an dreams involvin2 anll unpleasant emotion.i' This is emotionally adaptivemechanism also leaves room for consistentwith many-patients' reports that their night- the possibility that somedream disturbancesare adap- mares involve intensification of unpleasantemotions 753 754 ABNORMALSLEEP

=- Table 66-1. CUNICAl CRITERIA FOR NIGHTMARE DISORDER DSM-IVDiagnostic Criteria for Nightmare ICSD-RDiagnostic Criteria for Nightmares Disorder (307.47) (307.47-0) i A. Repeated awakenings from the major sleep period or naps A. 1ne patient has at least one episode of sudden awakening ~ with detailed recall of extended and extremely frightening from sleep with intense fear, anxiety, and feeling of impending dreams, usually involving threats to survival, security, or se1f- harm. 1 esteem. The awakenings generally occur during the second half of B. The patient has immediate recall of frightening dream context the sleep peri~. ., . .. C Full alertness occurs Immediately upon awakening, with little B. On awakening from the frightening dreams, the indiVIdual confusion or disorientation. rapidly becomes oriented and alert (in contrast to the confusion .. . and disorientation seen in Sleep Terror Disorder and some forms D. Associated features include at least one of the folloWIng: of epilepsy). . Return.tosleep after ~ episodeis delayedand not.rapid I disturb I . from The episode occurs durIng the latter half of the habitual sleep C ""-- dream . &1..- . Inc. experIence, or ute: seep ance resu ting period the awakening, causes clinically significant distress or impairment in social.occupational. or otherimportant areas of function. E. Polysomnographicmonitoring demonstrates the following: . . An abrupt awakening from at least 10 min of REM sleep D. The nightmares do not occur exclUSIvely during the course of . Mild tachycardia and tachypnea during the episode another mental disorder (e.g., a delirium, Posttraumatic Stress . Absence of epileptic activity in association with the disorder Disorder) and are not due to the direct physiological effects of a . substance (e.g., a drug of abuse, a medication) or a general F. Other sleep disorders, such as sleep terrors and sleepwalking, medical condition. can occur.

Data from American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Washington, DC: American Psychiatric Association Press; 1994; and International Oassitication of Sleep Disorders-Revised: Diagnostic and Coding Manual. RochesteJ< Minn: American Sleep Disorders Association; 1997. such as extreme sadnessor anger; fear nevertheless nosed adult nightmaredisorder population (e.g.,"one or remainsthe most frequently reported emotion.26 more nightmaresper week"}-prevalence estimatesare consistentlyelevated, for example,2 to 6% in college students34.35and about 4% in adults sampledrandomly Prevalenceand Frequency in Iceland, Sweden, Belgium,31and Austria.38When the question is put as "often or always," young adult Estimatesof nightmare prevalenceare complicated prevalenceis still 2 to 5%, whereasthat of adult and by the variety of populations studied and variations in elderly samples is only 1 to 2%.29These figures are the use of frequency criteria. Lifetime prevalencefor completely in line with estimatesthat 4 to 8% of the a nightmare experiencein the general population is general population have a "current problem" with unknown but may well approach100%. If we consider nightmares,about 6% have a "past problem,"~l and only attack dreams,which are one of the most common about 4% of patients spontaneouslyreport a complaint nightmare themes,the lifetime prevalencevaries from of nightmaresto their physicians.4Z 67%'Z1to 90%.28Pursuit, a closely related, highly dis- Nightmare prevalencemay be elevated in clinical turbing theme,has a lifetime prevalenceof 92%among populations, for example, 25% of both chronic male women and 85%among men.:za Age is clearly a mediat- ing factor; children. young adult, and adult and elderly alcoholic patients and female alcohol and drug users report nightmares"every few nights" on the Minnesota groups have nightmares" at least sometimes" with a Multiphasic Personality Inventory (MMPI).~ 44 How- prevalenceof 30 to 90%, 40 to 60% and 60 to 68% ever, other findings of elevatedprevalence are difficult respectively.19 Nightmares are both more prevalent and more fre- to assessbecause a frequencycriterion is not specified, quent in childhood. In a clinical context,3Owhere niJtht- for example, approximately 24% of nonpsychotic pa- mare problemswere defined as lasting for longer than tients seen in psychiatric emergencyservices report 3 months, their prevalencewas 24% for ages 2 to 5, nightmares,but with an unknown frequency.45 41% for ages6 to 10,and 22%for age 11years. Figures Nightmare frequencyis almost always assessedby of 5 to 30% (for "often or always") and 30 to 90% retrospectiveself-report, for example, the number of (for" at least sometimes")have also been reported for nightmaresin the previousweek, month, or year.When children.19 Two surveys'l.32 indicate that 20 to 30% of comnared to results from daily home 1025,however, 5- to 12-year-oldchildren have at least one nightmare retroSpectiveself-reports underestimatecurrent nightmare in any 6-monthperiod. We found a large genderdiffer- frequency by a factor of 2.5 in young adults36to a factor of ence in the recall ("sometimes" or "often") of dis- over 10 in the healthy elderly.46In general, a I-month turbing dreamsat age13 (boys:25% vs. girls: 40%)and retrospective estimate is closer to the estimate provided age 16 (20%vs. 40%)in the samecohort.33 by daily logs than is a I2-month retrospective estimate, Among adults, prevalencenevertheless is high (8 to and is thus the preferred standard for retrospective 25%) when frequenciesof "one or more per month" assessment. Note, however, that because nightmare are considered, as in several studies of college and prevalence and frequency are both seriously underesti- university students.:M-36Even for higher frequencies- mated by such instruments, daily logs are the method which likely correspond to much of the underdiag- of choice. t ~ DREAMINcDJSORoERS 755

Pathophysiology especially over posterior sites. Using a sazlp-average reJermcemontage, nightmare sections had higher fast The one available laboratory study of nightJnares21 beta (21 to 31 Hz) power over frontotemporal regions. indicatesmoderate arousal-in the form of increased The alpha pattern appearsto be an amplification of the heart (HR) and respiration (RR) rates-during some "classicalposterior alpha" of quiet rest49that has been nightmare episodes,but unexpectedlylow arousal in observedfor normal REM sleepwith an atypical exten- most others. Although these early findings constitute sion from posterior into frontal sites.!II the principal empirical basis for diagnostic guidelines Our subjects demonstrated even less sympathetic . such as the DSM-IV, there are serious problems with arousal during nightmaresthan did those of Fisher et the work. such as the inclusion of psychiatric and al., likely becausethey were relatively healthy and post-traumaticstress disorder (PI'SD) patients in the untraumatized.The co-occurrenceof cortical activation with minimal autonomic change during nightmares - study sample. ~ Wf!47.41 Undertooka replication and extensionof this may reflect a type of adaptive dissociation between ~. early work with a nonpsychiatricsample. Recordings imagery and emotion similar to that attainedby behav- t of HR and RR during nine subjects' nightmare and ioral therapiessuch as systematicdesensitization and ~ non-nightmareREM sleep episodesconfirmed a mod- flooding. Sympatheticinhibition during cortical proc- essing of potentililly anxiogenic imagery may, in fact. ~.. - mares.elate levelMean of sympatheticHR for nightmare arousal REM during sleep some was night- ele- "desomatize"that imagery.n. 51 r vated (by about 6 bpm) only for the 3 mins prior to . awakening(Fig. 66-1).Most subjects(78%) showed HR ; accelerationduring nightmare steep,whereas the same Personality numbershowed HR decelerationsduring non-nightmare REM sleep.Mean RR was only marginally higher for Although many studies suggestweak to moderate the last 3 min before awakening. relationshipsbetween nightmare frequencyand meas- We also found changesin cortical activity during ures of psychopathology, n. 5Z.53 others do not.11.36, " The nightmares."EEG samples from the last 2 min of night- seemingly weak relationships between nightmares and mare sleep,when comparedwith control samplesus- psychopathology likely reflect mediating factors, ing a linked-earrtftrtnce montage,had generally higher among which two-chronicity and distress-have been absolute and relative alpha (8 to 13 Hz) power, but given some attention.

-+- Nightmare

- . .Control

~ a. -m .s nJ ex:: 1:: nJ CD ::z:

p=.06 "..03 p=.tU 756 ABNORMAL SLEEP

Nightmare ChrOnicity. Adults with a lifelong his- Table 66-2. DRUGS REPORTEDTO INCREASE --;~ tory of frequent nightmares compose a subgroup of FREQUENCYOF NIGHTMARES idiopathic nightmare sufferas who manifest more psy- chopatholosical symptoms than matched controls Drug Function = without nightmares, for example, higher neuroticism ThiodUxene Neuroleptic 88 - and MMPI psychopathology scores.5Z.55However, Hart- BetaxoIol Beta bloc:ker 89 mann22found that no one measure of psychopathology Carbachol ~1inergic agent 89 adequately describes these individuals. He and his col- Fluoxetine Antidepressant 90 leagues proposed22." a general "boundary permeabil- Naproxen Nonsteroidal anti- 92 ity" personality dimension, which at one extreme inflammatoryagent Verapamil Antimigraine agent 93 ("thin boundaries") characterizes lifelong sufferers. Triazolam Benzodiazepine hypnotic 238, 239 "Thin boundary" individuals are more open. sensitive, 240 and vulnerable to intrusions than "thick boundary" Nitrazepam Benzodiazepine hypnotic 94 subjects, rendering them more sensitive to events not ~~ An~~c ~ usually viewed as traumatic.22Nightmare frequency is 96 positively related to "thin boundary" scores,57.,. as well as to hypnotic ability, absorption in fantasy and aesthetic experiences, and creativity." to normalize sleep. In fact, 29 (29%) of a group of 100 Nightmare Distress.Nightmare frequencyand wak- alcoholic patients reported further drinking to alleviate ing distressover one's nightmares are not equivalent. ~~tmares.~ To illustrate, one 39-year-old man had no Ni~htmare frequency is only moderately related to . cu1ty initiating sleep while abstaining, but he was nightmare distress.II. 36Subjects may have only few awakened often by nightmares that prevented him nightmares(e.g., one per month) yet report high levels from returning to sleep. "The nightmares were of of distress, or report many nightmares (e.g., one or somebody trying to hurt him. He would wake up more per week) yet low levels of distress. It is the thrashing and in a sweat and spend the rest of the nightmare distressfactor that is si~cantly related to night pacing and smoking. After he had started drink- psychopathology,not necessarilythe frequencyfactor.11 ing . . . he could get no sleep unless he was dnmk."77(pt99)This relationship is also of critical impor- tance because of the danger of alcohol self-medication Effectsof Drugs and Alcohol for PTSI)1I." and for other nightmare-producingdisor- ders. " Numerous classesof drugs trigger nightmares and Vivid and macabre dreaming may be central to the bizarre dreams, including catecholaminergic agents, delirium tremens (DTs) of acute alcohol withdrawal.80 I beta blockers,some antidepressants,barbiturates, and Because alcohol suppresses REM sleep, and the per- alcohol. Among catecholaminergicagents, reserpine, centage of REM sleep (particularly at sleep onset) is thioridazine,and levodopa(L-dOpa) are all occasionally extremely elevated in patients with DTs,"' 81.82 a theory -,'.. associatedwith vivid dreams and nightmares/60-63as of DTs hallucinations emphasizing REM rebound and are beta blockers such as betaxoloI. metropoloI. biso- intrusion of dreaming into wakefulness has been pro- prolol, and propranolol.'-' Among the antidepres- posed.IS Case studies strongly suggestthat hallucina- ,1'1 sants/ bupropion leads to more vivid dreams and tions may seem to continue uninterrupted from an ongo- nightmaresthan do other antidepressants.'"7'0 Bedtime ing nightmare." DTs sleep appears to be a mixture of administrationof tricyclic and neuroleptic agentsleads REM sleep with "stage 1 REM sleep with tonic EMG to a higher recall of fri~tening dreams than when (electromyography1" which distingUishes it from the these are taken in two daily doses/71.72 even though sleep of alcoholic patients without DTS.MSome have ~-1 "'--~. --- 11 --~--; .J-.- ~._. -"'1~ 1 r--;... failed to observe this pattern. however.85." The similar- and tricyclic drugs appearto render dream affect more ity of the sleep of patients with DTs to that of REM dysphoric. rather than to increasedream recall per se. sleep behavior disorder (RBD) has also been noted. r1 Withdrawal from barbituratesis associatedwith REM The neuropharmacological basis of drug-induced or rebound,vivid dreaming,and nightmares.'"74 A hy- withdrawal-associated disturbed dreaming remains pothesishas been advancedthat barbiturate suppres- unclear. There may be an imbalance among various sion of REM sleep,much as with alcohol, causesREM neurotransmitter systems such that nightmares are pro- sleep rebound after discontinuation of the drug and duced by reduced brain norepinephrine and serotonin consequentlylonger and more vivid dreams.75Several or increased dopamine and acetylcholine, or a combi- casestudies have alerted physiciansto the nightmare- nation of these.22 inducing effectsof specificsubstances (Table 66-2). Sleepand dream disturbancesfollow alcohol with- drawal. Alcoholic patients report more vivid dreams Recurrent Dreaming and Nightmares and nightmares following withdrawal than they do during ingestion; although theseare more frequent in Many theories converge on the view that recurrent ~e week following withdrawal, they are still present dreams reflect a lack of progress in resolving daytime m subsequentweeks. The nightmaresand insomnia of emotional preoccupations. Failures in an adaptive func- withdrawal can lead to resumeddrinking in an attempt tion of dreaming may be indicated by a dream series DREAMINGDISORDERS 757

with a repetitive pattern, such as the stating and restat- conflict resolution has traditionally been the treatment ing of a problem, yet no depiction of progress.Four of choice,IO6,107 it lacks empirical support. On the other I' points on the "repetition dimension" of dream con- hand, there is much support for diverse cognitive- tent" may, in fact, reflect diffe~t degrees?f psycho- behavioral interventions that require six or fewer ses- pathological severity. Repetitivedreams, such as post- sions. Systematic desensitization and relaxation tech- traumatic nightmares,depict-over numerous, highly niques, used to countercondition a relaxation response similar versions--an unresolvedexperience, for exam- to anxiety-provoking nightmare contents, have been t ple, a motor vehicle accidentor war trauma. Recurrent effective in several case studies and in two controlled dreamsdepict conflicts or stressorsmetaphorically over studies.54.108Imagery rehearsal, which teaches patients time, and are also primarily unpleasantin nature.9&.99 to change their remembered nightmares and to re- Themost frequentrecurrent dreams of adults are pseu- hearse new scenarios, has reduced both nightmare dis- donightmarish:being endangered(e.g., chased, threat- tress and frequencyin a recentseries of controlled enedwith injury), being alone and trapped (e.g.,in an studies.17,109, 110 Other treatments with some empirical elevator), facing natural forces (e.g., volcanic erup- support are lucid dreaming,1I1eye movement desensiti- tions), losing one's teeth. Dreams with less recur- zationand reprocessing,lU and hypnosis.1I3 rence-recurrentthemes and recurrentcontents-both ex- tend over long seriesand are not so clearly associated with psychopathology.However, they may still have DISTURBED DREAMING IN adaptivefunctions.'" OTHER SLEEP DISORDERS Case studies have described changesin repetitive dreamelements toward a progressivepattern as a func- The full extent to which dreaming and various sleep tion of successfulpsychotherapy,1oo as have laboratory disorders influence one another remains largely un- studiesof women dealing successfullywith depressive studied. For severalsleep disorders, disturbed dream- reactions to divorce. lOt,1OZ Similarly, subjects with recur- ing has been identified as a primary symptom (Table rent dreams show less successfuladaptation on mea- 66-3). There are also a number of sleep problems for suresof anxiety,depression, personal adjustment,and which disturbed dreaming is a salient factor even life-events stress than those without recurrent though its pathophysiologicalimportance has not been dreams.1O3.11M The maintained cessation of recurrent determined. Finally, there are conditions for which dreamingmay also reflect an upturn in well-being.11M dreaming is disturbed, but which nevertheless fall within the normal range of functioning. In all likeli- hood, whether patients with a particular condition Treatment spontaneouslydisclose that they also suffer from dis- A wide variety of trea~ents for nightmares have turbed dreaming will be mitigated by various psycho- been reported.23o105 Although psychotherapyaimed at logical, sociological,and cultural factors.Many patients

Table 66-3. SLEEPDISORDERS IN WHICH DREAMING IS DISTURBED Sleep Disorder Code Stage Prevalence Essential Features Nightmaredisorder 307.47-0(ICSD) REM. 2 Children: >-30%;young adults: Frighteningdreams; awakening 2-5% (seetext) Sleep terrors .307.46-1 (ICSD) 3,4 Oilldren: 3%; adults: sl% Sudden arousal; piercing scream or ay; autonomic and behavioral manifestationsof intensefear Terrifyinghypnagogic 307.47-4(ICSD) Sleeponset Rare;narcolepsy: 4-8% Terrifyingdreams simi1ar to hallucinations thosefrom sleep Post-traumaticstress 309.81(DSM-IV) REM. 2. 3, 4 Lifetime: 1-14%;at-risk Persistentreexperien<:i;ng..of a disorder nightmares subjects: 3-5no traumatic event, 1lICIUamg recurrent nightmares Narcolepsy dreams 347 (ICSD) REM O.(J3-().16% Excessive sleepiness, cataplexy, sleep paralysis, hypnagogic hallucinations Sleep paralysis 780.56-2 (ICSD) Sleep onset Isolated. nonna1s; l/lifetime in Paralysis of voluntary muscles; or offset 40-50%; familial: rare acute anxiety (with or without dleams)is common REM sleepbehavior disorder 780.59-0(ICSD) REM Rare Intermittent lossof REM sleep; muscleatonia; elaborate motor activity associated with dream (nightmare) mentation Sleep starts 3IJ1.47-2(ICSD) Sleep onset Lifetime: 60-'70%; extreme Sudden brief jerks associated form: rare with sensory flash. hypnagogic dream, or feeling of falling DSM-IV. DiAgnostic11M Stlltisticlll MJmulIl of Merltlll Disorders. Fourth Edition»; ICSD. International Oassmcation of Sleep Disorders.IOG 758 ABNORMAL SLEEP ,:, attribute personalor spiritual significanceto dreamsor awakenings might be a means of defending against consider them to reflect their "state of sanity" and anxious dream content a type of "preemptive strike" may therefore hesitate to speak openly about them. against impending nightmares. In the laboratory, Sensitivity to such factors could substantially facilitate Greenberg'spatients demonstratedrepeated spontane- researchon. and treatmentof, dream disturbances. ous awakeningsfrom REM sleep,that is, on an average of 70% of REM episodes,but no consistentreduction in REM sleep time. Treatmentreduced the number of Post-TraumaticStress Disorder Nightmares REM awakenings almost by half and reduced REM Recurrent anxiety dreams plague the vast majority sleeptime slightly. of PTSD patients.U4 Disturbed dreaming may, in fact, Three casesof dream-interruption insomnia were describedby Cartwrightl35and ~o by Lavie et al.l28In be the hallmark of delayed PTSD115,116; the content of the latter study,2 of 11patients under study for trauma disturbing dreams (e.g., reliving combat), as well as manifestedREM-related awakenings; these were also associated sleep disruptions (e.g., nocturnal awaken- ings, fear of sleep),117. 118 may reinforce the illness. A the only two patients who experienced war-related related hypothesis is that disruption of REM sleep con- nightmares in the laboratory. Interestingly, most REM interruptions in this study were preceded by increased trol mechanisms-including those governing dream- HR. as is the case for nightmare awakenings.21Cart- ing-is central to PTSD pathophysiology.119Evidence wright135reported that psychotherapy focusing on the that PTSD produces a variety of changes in REM sleep content of patients' dreams and nightmares is success- architecture and in the recall, content, and affective ful in alleviating their insomnia. The notion that insom- quality of dreaming is consistent with both of these nia may be due to the expression of conflicts in dreams hypotheses. There is evidence of decreased dream re- call from REM sleep,12O,121 as well as increasednight- has been observed by clinicians, even prior to the dis- covery of REM sleep.136 mares or sleep terrors in early REM sleep episodes122 and in stages 2, 3, and 4 nonrapid eye movement Out of 983 consecutive patients seen at the Sacre- (NREM) sleep. uo.123. 124 There is also either a decreasem- 125 Coeur sleep clinic in Montreal from March 1994 to or an increasel211.123 in REM sleep latency, an increase August 1997, 14 (1.4%) were found to conform to a in REM sleep density,12O.121 a decrease in the number pattern suggestive of dream-interruption insomnia and length of REM sleep periods,l26,127 and a decrease (meanage: 53.5 j: 15.7years). Twelve of thesepatients in total REM sleep time.l211.128 Any of these associated (85.~k) were male; 2 (14.3%) were female. Of 10 pa- tients who had neither apneas (n = 1; index greater than changes in REM sleep might account for, or be a conse- 5) nor periodic limb movements in sleep (n = 3; index quence of, the characteristic dream disturbance in PTSD. The fact that therapeutic interventions directed greater than 10), two distinct, but not necessarily inde- specifically at nightmares (e.g., imagery rehearsal) can pendent, patterns of REM interruption were observed (Fig. 66-2). One (panel A) consists of recurrent awaken- significantly reduce their frequency and associated ings early in the REM episode and subsequent cur- sleep problemsl2.9is also consistent with the notion that tailment of the episode. This appears as low sleep PTSD is, at root. a disturbance of dreaming or REM sleep, or both. efficiency, low REM percentage, and high REM effi- It is noteworthy that PTSD patients sometimes re- ciency. The second pattern (panel B) is the more com- mon of the two and consists of repeated shorter arous- port nightmares after awakenings from early in the als throughout the REM episode. This appears as sleep episode,uo including after awakenings from NREM Sleep,l20which is where sleep terrors are typi- moderate to high sleep efficiency, high REM percent- cally found.131In fact, PTSD nightmare-associated be- age, and very low REM efficiency. With so few clinical reports of dream-interruption haviors, such as autonomic activation, gross body movements, confused arousal, and partial amnesia, insomnia, its exact prevalence is not known. However, if the problem is, indeed, a variant of nightmare disor- greatly resemble those of sleep terrors,l32 suggesting that they may be a phenomenon intermediate between der, its prevalence may be substantial, given the high co-morbidity of insomnia with nightmares in the gen- idiopathic nightmares and sleep terrors. A more com- eral population. In one sample of 1049 French insomnia prehensive definition of overlapping parasomnic states patients, 18.3% suffered from nightmares.137Many oth- may be required to fully explain PTSD.133 ers have confirmed relationships between nightmares and variables associated with insomnia (e.g., sleep- Dream-InterruptionInsomnia onset latency, night awakenings, restless sleep).35-117.138 Successfully treated nightmare patients also often re- Greenbergl34proposed a subcategory of insomnia, port improvements in sleep qUality.17.139 dream-interruption insomnia, on the basis of five pa- Whether or how nightmares may trigger dream- tients who reportedawakening from sleep/I every hour interruption insomnia is not known. Althou~ it is or so" throughout the night Four of these patients clear that nightmares may generate"sleep distress"18 reported a period of intense nightmares just before or a disproportionate fear of the dark,140 which later onset of their insomnia; nightmares then disappeared may generalizeinto sleep-onsetdifficulties, an ability but subsequentlyreappeared after treatment with ei- to preempt nightmares would seem to require sus- ther chlordiazepoxide(Librium) or diazepam (Valium) tained vigilance or self-monitoring throughout sleep. in three of four cases.This pattern suggestedthat the Another possibility is that inhibitory REM sleep pro- . -

DREAMINGDIsoRDERS 759

Hypnogram A

I ! j I I . , . 120 180 240 300 420 480 S4O min j :

HypnogramB l ~ ~ ~~ 1 I I I ~ 2 I I~

:3

4 REMP 0 110 120 180 240 300 380 420 480 S4O B min Figur866-2. Hypnogramsof two forms of dream-interruptioninIomnia. A illustratesa form c:onsisdngof rec:ummtawakenings early in the REM epIIode with aub8equentcurtailment of the episode.This appearspolYlOmnographically as low Ileep effidency,low REM percentage (REMP),and high REM efficiency.B illustratesthe more commonof the two forms: a pattern of repeatedbrief arousalsthroughout the REM epiIode.This appearsas moderateto high sleepefficiency, high KEMP,and very low REM efficiency. cessesare unable to completely suppressthe "surge- gory of experiences referred to as existential dreams.14 145 like" nature of anxious dream contentUor that some They are characterizedby distressing emotions (e.g., particularities of the dream content are more prone to sadness,despair, guilt), salient bodily feelings (e.g., provoke REM sleep miaoarousalsor awakenings.The ineffectuality of action. paralysis),and failures in goal dreamcontent of someinsomniac patients may also be attainment. There is also separationand loss, the ap- SOtightly coupled to activating processesthat even pearanceof deceasedfamily figures, and an increased minor dream anxieties may trigger an arousal. This sensoryvividness that may culminate in an intensely idea is supported by the finding that for insomnia real ending~ften with an awakening. This dream patientsvivid, mghtening, and disrupted dreaming is type is distinct from the anxietytype, identified by the correlatedwith shorterREM segmentsand higher REM sameanalytical procedure,which resemblesthe classic densities,whereas for narcolepsypatients it is not.!4! idiopathic nightmare. Existential dreams resemble Yetanother possibility is that insomnia producesnight- nightmares in their emotional and sensorialintensity mares,particularly insomnia that involves sleep frag- and in their associationof vivid apparent reality with mentationand maintenancedifficulties. Sleepfragmen- arousalsfrom sleep.They differ from them primarily tation is also known to characterize sub1ectswith in the specific emotions, bodily feelings, and typical &equentsnoring-the latter, in turn, is strongly corre- lated with nightmares.- 142.10 Induced sleepfragmenta- themes that they depict. The clinical importance of existentialdreams is their appearanceduring bereave- tion also producessleep paralysis experiences, most of ment, which involves a range of distressingemotions which involve anxiety or terror.1" other than fear. Bereavementis also characterizedby haIIucinationsand vivid feelingsof the presenceof the Existential(Grief) Dreams deceasedin both dreamingand waking states.I'" 141 Employing a method of polythetic (multiattribute) Theseclosely resemblethe presencedreams of persons classification, Kuiken and co-workers identified a cate- with narcolepsyand sleep paralysis (seeNarcolepsy). 760 ABNORMALSLEEP

frequently than before" with the periodic impression of 1/dreaming all night."J53(p18O)Brain-damaged patients also may report more continuous dreaming, that is, dreaming the same content throughout the night, de- spite intervening episodes of wakefulness.153-155Al- though brain lesions are not typically suspected in epic-dreaming patients, the neuropsychological evi- dence points to involvement of the anterior limbic sys- tem and suggests that further clues to its cause may be found in associated emotional disturbances (e.g., alexithymia, dysthymia) in these patients. Treatments for epic dreaming (cognitive, hypnosis, relaxation, Epic Dreaming medications) have proved largely ineffective.1!O Long, rambling dream narratives are not unusual in laboratory studies. Nor is the occasional patient Sleep-Wake Transition Disturbances complaint of "dreaming all night long" and feeling tired in the morning as a result. In a series of 20 ,j Severalinterrelated dream disturbancesoccur at the Ji patients,Schenck and Mahowald1!Oidentified a clinical transitions into or out of sleep. Theseshare the attri- .. ;, entity-" epic dreaming"-in which relentlessdream- butes of vivid, often intensely real, sensory imagery ing and daytime fatigue are associatedin a chronic and disturbing affectssuch as fear.It may be their close fashion.151 Thesepatients feel that they dream all night proximity to wakefulnessthat colorsthese images with and complain of marked daytime fatigue. Their dreams a distinctive reality quality, that is, there may be an typically involve constant, trivial, or banal physical interleaving or boundary dissociation of sleep-wake activity, such as repetitive housework or endlesswalk- processesat this time. Theremight be, for example,an ing through snow or mud, although intensesensations intrusion of a reality perception into sleep or of a of accelerationor spinning can also occur. Patients dreamedobject or characterinto wakefulness(d. refer- describe having a II dream motor running all night ences 156, 157). The nature of the intruding compo- long," or "not having the mind shut down during the nents may well determine the distinctivenessof the night."l50These dreams occur nightly in 90%of affected transition disturbance,including typical or odd combi- patients and 4 nights a week in the other 10%.1!OThe nations such as a frightening hypnagogicimage termi- repetitive quality of epic dreamsis reminiscentof some nating in a sleep start or incomprehensiblesleep-talk- recurrent dream themesand even of somenightmares. ing accompanyingsleep paralysis. Nightmares are, in fact, reported by 70% of thesepa- tients, but the epic dreaming pattern is the primary complaint in most cases.l50Emotional arousal is Sleep Starts strangely absent from epic dreams. Nonetheless,the Sleep starts, also known as predormital or hypnic associatedsensations of fatigue or exhaustion,as well myoclonus or hypnagogic or hypnic jerks, are brief as the seeminglyendless repetitiveness of the dreams, phasic contractions of the musclesof the legs, arms, may engenderdistress and motivate a clinical consulta- face, or neck that occur at sleep onset.They are often tion. associatedwith brief, albeit vivid and impactful, dream In most cases,polysomnographic evaluation reveals events. Perhapsthe most common of these events is no clinical abnormalities, apart from occasional PLMS t.lteillusion of suddenly falling that incites a vigorous (10%) and sleep-disordered breathing (10%); the prob- and startling jerk. Brief sensory flashes also occur; lem is also more common in women (85%) than in men sometimesthey may be somatic in nature and some- (15%).150 The underlying mechanisms of the disorder what difficult to describe.A subjectin Oswald's study, remain unknown. However, comparative studies of for example, reported" a stran~e sensationof some- epic dreams with normal dreams, nightmares, and re- thing passingor flowing through his body, something current dreams might shed light on possible patho- 'hot' and 'bright."'158(pM)The patients of Sander et al. physiology, for example, whether the recurrent motor reported "electric shock-like sensationsin the chest" imagery differs from that found in normal dreamingl52 and "focal itchy, sharp, pinprick-like sensationsthat or whether epic dreams are simply long nightmares may occur anywhere."159(p690)More complex hypna- with an absence of affective intensification. gogic imagesmay also accompanysleep starts. Changes in dreaming that are possibly related to Mild starts are a normal~ven universal-feature this disturbance occur in brain-Iesioned patients153and of falling asleep,and a prevalenceas high as 60 to 70% include increases in both the frequency and the viv- idness of dream imagery.1M. 155 Either of these changes hasbeen cited.160 More extremestarts that can engender difficulties in initiating sleep161have been describedby might render dreaming more memorable and more likely to be perceived as having been continuous Critchley: through the night. For example, Solms's patient 136, I refer to violent, abrupt sensoryand motor phe- who sustained severe bilateral brain damage following nomena which come on quite unexpectedly,so as to a motor vehicle accident, reported dreaming" far more shatter the backgroundof sleeping.The sudden event DREAMINGDISORDERS 761

of a hallucinatory crash of noise or bang localized be an entity of somekind which would harm me if the within the skull in an explosive fashion is not unfamil- dream continued,so I made a huge effort to move my iar. Or it may be a sudden blinding flash of light.I63(J>UIS) arms and woke up out of the dream.

Critchley's claim that these dramatic sensory phe- The suffering during such episodesis exacerbated nomena are more common in subjectswith sensory by the victim's simultaneoussense of wakefulnessand problems,for example, loud noises among deaf per- inability to move or call for help. Further, the intense sons,has not been systematicallystudied. anxiety may seriously disrupt sleep.For example,re- It is not known whether chronic sleep starts are current THHs may disrupt sleep onset sufficiently to primarily a disturbanceof motor systems,pemaps akin produce sleep-onsetinsomnia.l60 And, as the second to PLMS, or a disturbance of imagery systems,such example illustrates, the realism of the dream leads that intenseimages provoke the disruptive reflex activ- readily to attributions about "real" assaultsby spiritual ity. Electroencephalographic(EEG) events have been entities, especiallyif the individual lives in a context noted to accompanysleep Starts,l58but, more system- conducive to such beliefs.l_l67Prevalence figures for atic studiesof sleepstarts and the variety of BEGburst THHs are not available, but an estimate for patients patternsthat can accompanydrowsinessl63 are needed with narcolepsyis 4 to 8%.29 to clarify this issue.

Terrifying Hypnagogic Hallucinations Sleep Paralysis Physiological mechanisms of sleep paralysis (SP) Terrifying hypnagogichallucinations (TIffis) are ter- have been studied in some detail,l68,169 but the relation- rifying dreams similar to those from REM sleep; after ship of SP to disturbed dreaming remains unclear. SP a sudden awakening at sleep onset there is prompt is a cardinal symptom of narcolepsy and also occurs in recall of frightening content.l60As they arise from healthy persons. Patients seldom present for symptoms sleep-onsetREM (SOREM)episodes, they may be ag- of SP alone, although they may when the frequency of gravated by factors that predispose to this type of their episodes increases, for example, to one per day. sleep,for example,Withdrawal from REM-suppressant The clinical disorder of sleepparalysis, either familial or medication,chronic sleepdeprivation, sleepfragmenta- isolated,occurs at sleep onset or upon awakening from tion, narcolepsy.Other sleep and medical disorders sleep, whereas "normal" feelings of paralysis or inef- may accompany the condition. Content analyses of fectuality are a common feature of dreaming more THHs are lacking, but clinical and anecdotalreports generally16and, especially, of nightmares.1?OAccording suggestthat the themesof attack and aggressionfound to some,l71paralysis feelings render hypnagogic hallu- in REM sleep nightmaresare common.THHs are per- cinations threatening or terrifying in nature. Frighten- haps more anxiety-provoking than most nightmares ing SP episodes have also been referred to as sleep becauseof (1) a vivid senseof reality related to their paralysis nightmares,and their role in the misdiagnosis closeproximity to wakefulness,and (2) frequently ac- of hysteria and allegations of abuse described.l72 companying feelings of paralysis. These features are Although psychopathology does not seem to be a illustrated in the two following examples. direct cause of Sp'I13sleep-related life habits are associ- A Case of Severe THH in a 36-Year-Old Woman ated with their occurrence in non-narcoleptic popula- With PT50.At age 19, she was abductedand for more tions, I'. for example, poor sleep quality, insufficient than 3 days, raped, beaten.burned, and subjectedto sleep, and a proclivity to daytime sleep-all factors death threats (Russian roulette) by motorcycle gang that mav favor the occurrence of SOREM episodes. 1'. members.Although she regularly reexperiencedthese In fact, isolated SP episodeshave been elicited experi- horrors through flashbacks and nightmares, even mentally (on 72% of trials) by a schedule of sleep worse were the THHs with paralysis occurring as she interruptions producing SOREM.l" Of the six SP epi- returned to sleep after a nightmare. She felt as if she sodesinduced by this method, five occurredduring a were awake,aroused, and terrified, yet unable to move; SOREMepisode: The one exceptionsuggests that there time seemedto be extremely drawn out as she experi- may neverthelessbe other, subtler factorscontributing enced "replays" of her torturous experiencein slow to SP. motion.164 One such factor may be psychopathological, al- THHs in a Healthy 26-Year-Old Practitioner of Eso- though this likely influencesSP indirectly, by its influ- tericism. She reported having had several lHHs, but enceon stressand overwork and its subsequentdisrup- not daytime sleepinessor cataplexy.Her nni included tive effectson sleep.In Anotherfactor may be rapid paralysis and vivid tactile, thermal, and auditory im- resetting of the circadian clock, as is the case with ages associatedwith the sense of an assault by an rapid time zone change,175or sleeping in the supine intruder: position.1n. 176However, the nature and intensity of imagery generation in both wakefulness and sleep also I had just closedmy eyeswhen suddenly I felt the appears to playa role in the occurrence and frequency presenceof a man behind me. He held me by the hair and pulled it. He had a knife to my throat; I could feel of SP.l11Ulginiltiveness, as indexed by standardized ques- the cold of the blade. He threatenedme by saying: tionnaires, and vividness of nighttime ima8ery, as "You bitch. If you try to move I will kill you." I tried measured by self-reported frequencies of nightmares to saeam but was completelyunable. I knew it must and sleep terrors and vividness of dream imagery, are 762 ABNORMALSLEEP , two personalitYfactors found to be mostpredictive of large variability and to clarify the role of sociocultural SP occurrenceand frequency in a large multivariate factors in the experiencingand reporting of SF. ! study of collegestudents.l73 ". SP is typically accompaniedby vivid hypnagogic Somniloquy With Dream Content hallucinations.In fact, it is rare to find SP in the ab- senceof other hallucinatory activity. Spanos et al.l73 Sleep-talking has been observed in all stages of found that 1.6%(of 387) subjectsexperienced SP with- sleep, but especially in NREM stages2, 3, and 4.181 out other attributes. Similarly, of the six experimental Arkin181identified various orders of concordancebe- SP episodesdescribed, all but one included auditory tween sleep speechand later dream reports. For first- or visual hallucinationsand unpleasantemotions.l44 On order concordancessleep speechexactly .matchescon- the other hand, it is not true that most hypnagogic tent in the dream,for example,a subjectshouting "No! hallucinationsare accompaniedby SF.Given this asso- No!" who dreamed of shouting these words when ciation of SP with hypnagogic hallucinations,it is un- seeing her baby fall from the bed. For second-order clear whether SP is, as some have suggested,l66.111 a concordancesa conceptualor emotional link between typeof perception,that is, of ongoing REM sleepmuscle sleep speechand the dream is preserved,for example, atonia. Paralysissensations-much like dreamedemo- a nightmare patient dreamed repeatedly of trying to tions and other sensations--mllYbe at leastpartially hal- yell "Burglars!" but in reality called out "Mama!" Ab- luci7UZtory.This could account for why SP is often re- sence of concordanceis also seen: one study of 28 ported to be associated with odd feelings of chronic sleep-talkersfound it in 16.7%of REM, 32.9% oppression.pressure on the chestand other body parts, of stage2, and 38.5%of stage3/4 sleepepisodes. lit As even violent choking and beating. It could also explain with SP,it remainsunknown why imagery and behav- how paralysis and felt ineffectuality appear in such a ior are dissociatedin this manner. variety in routine dreamsand nightmares.16 Prevalence Considerations. Multiple SP episodes False Awakening have a low prevalence,occurring "often or always" in only 0 to 1% of young adults and "at least sometimes" False awakenings are nowhere classified as patho- in 7 to 8% of young adults.2POn the other hand, the logical per se, but they are neverthelessdreaming dis- International Oassification of SleepDisorders-Revised turbances that can produce anxious reactions. Two' (ICSD-R)I60cites the lifetime prevalenceof SP at 40 to types of false awakening have been distinguishedpri- 50%,which is somewhathigher than other estimates. marily on the basis of the degree of anxious affect We found ratesof 25 to 36%in surveys of three univer- associated. 157.182 Both types typically depict the person sity psychologystudent groups (Table66-4), which are as (falsely)waking up from sleepor, in variations,from similar to the value of 26% reported for 208 Japanese a dream, and may engender some confusion while undergraduates,l78of 21% for 1798 Canadian under- dreaming about whether one is actually awake or graduates;73and of 34% for 200 sleep-disorderedpa- asleep. tients.I'" Type1 awakeningsare the more common type and Simple methodological differences may explain usually depict realistic instancesof the person waking someof the discrepanciesamong theseestimates. Even up in his or her habitual bed followed by, in many a minor change in wording on questionnaires (e.g., cases,depictions of activities such as dressing,eating replacing "transient paralysis" with "condition") can breakfast,and setting off for work. Somediscrepancy increase estimates by 5% (from 26 to 31%); use of a in the imagery may fully awaken the person with the culturally identifiable term for Sp, such as kanashibari surorisin2 realization that it was "just a dream." The in Japan. can increase the estimate by an additional 8% dreams are often repetitive, depicting a successionof (to 39%).1" The latter estimate corresponds well with awakeningsor of setting off for work. The philosopher those drawn from other cultures, for example, 3j'Okof Bertrand Russell, after having undergone anesthesia, 603 Hong Kong undergraduates reporting at least one reported seeming to have awakened hundreds of episode of "ghost oppression," the Chinese equivalent times.l83 of kanash~Dari.l"One survey of Newfoundland villagers Type2 false awakeningsare less pleasantthan type found as many as 62% admitting to "Old Hag" at- 1 in that the apparentawakenings in bed are accompa- tacks.IID Much more work is needed to explain this nied by a "stressed,electrified or tense" atmosphere

Table 66-4. LIFETIMEPREVAlENCE IN FOURSAMPlES OF SLEEPPARALYSIS ITEM "BEING HAlf AWAKE AND PARALyzeD" (TYPICAL DREAMS QUESTIONNAIRE) N Men Women Both Reference

Clinical sample 200 31.6 37.2 34.0 241 University sample 1 132 31.1 37.9 35.6 242 University sample 2 388 18.8 2!J.7 24.7 Nielsen, Zadra. &: Smith (unpublished data, 1998) University sample3 107 26.3 30.4 29.0 243 Totals!Averages 827 27.0 33.1 30.8 DREAMINGDISORDERS 763 and feelings of "foreboding or expectancy" that may abuse,188dream-reality confusions can also occur in be "apprehensiveor oppressively ominoUS."l51There healthy subjects.l89 may be hallucinations of ominous or anxiety-pro- The cause of disturbed dreaming in narcolepsy voking sounds, or strange apparitions of persons or likely has more to do with the fragmentationof REM sleepl90than it does with increasesin the intensity of monsters. REM sleep phasic activity; REM density in persons Both type 1 and type 2 false awakening are fre- with narcolepsy is in the normal range.191,192 In this quently associatedwith-experiences of separatingfrom the sleepingbody, or out-of-bodyexperience (OBE), and respect,disruption of REM sleepmechanisms in narco- of becoming aware of dreaming while dreaming, or lepsy resemblesthat of dream-interruption insomnia lucid dreaming.l51False awakenings are clearly not al- (seeabove). ways about a person'sown home and bed, becauseour Patientswith narcolepsyare thought to suffer from frightening and macabrehypnagogic hallucinations to researchteam has elicited them in laboratory subjects. a greater extent than are others.l93These may be as terrifying as REM sleep nightmares.l71Studies of their Pathological and Disturbed Lucid Dreaming contentl'l. 194reveal differences from the nocturnal dreams of healthy subjects:they contain less visual Lucid dreaming is occasionallyassociated with dis- and motor imagery,more negativeemotions, and more turbed or pathological reactions. Typically, lucid paralysis feelings. Nevertheless,SP and hypnagogic dreaming is perceptually vivid-the dreamer often hallucinationsoccur almost exclusivelyduring SOREM feels awake-with a limited capacity to control the episodes, as opposed to nocturnal REM sleep.l69A unfolding of some dreamedevents. It is often sponta- number of characteristic themes have also been neously triggered within a nightmare and can be used describedl93.195that seem typically nightmarish in na- in a therapy context to resolvethe distressingcontents ture, for example, human aggressors;threatening in- of recurrent nightmares.111However, some have re- sects,snakes, and other animals;and oppressivepres- ported diversenegative reactions associated with lucid ences. The majority of hallucinations reported by dreaming,including a type of "burnout" resulting from patients with narcolepsyconcern human beings (76%), too frequentintentional use of the mental state,mental animals (29.2%), reptiles (22.4%), and monsters or confusion.and "quasi-psychoticsplits with reality" in- duced by the overlapping of perceptual and dream- ghostsPresence (21.6%).195Imagery. Dreaming that a presencehas like mentation. and intense fear associatedwith the enteredthe premisesis closely associatedwith SP and loss of control of the vivid dream contents.l84 is thus one of the most frequent hallucination themes One reported casewith polysomnographicevalua- reported by personswith either narcolepsyor isolated tion involved a 28-year-old single man with lifelong or familial sleep paralysis.l70o 196,197 The intruder is often lucid dreaming who presented to a clinic because2 simply sensed as a presencemoving about near the years earlier he began to lose control of his lucid bed but without much visual or auditory detail (see dreams.lIS He could no longerescape from dreamag- reference193 for examples).More commonly,the pres- gressors,or avoid their beatings and shootings. He encesare associatedwith intense emotion. They may experienceduncontrollable sobbing and "being beaten be perceived as threatening,ransacking the premises, to a pulp."l1SHe would awake feeling that he "had or physically assaultingthe patient. been hit by a truck," with severeheadaches, muscle Personswith severenarcolepsy may experiencesuch pains, and exhaustion.Polysomnographic and psychi- horrors almostdaily. Their hallucinatoryvividness may atric tests proved normal, with the exception of some cause severe confusion about the objective reality of MMPI abnormalities. Psychotherapy and hypnotics events. Thus, if a proper diagnosis is not achieved were ineffective,but the antiepileptic diphenylhydan- and the patient not informed about the nature of the toin eliminated his symptoms. Adverse reactions to hallucinations, there may be a substantial emotional lucid dreaming appear to be rare, but they have not toll. Patients (and sometimes even physicians) may been studied systematicallyin either normal subjects take the hallucinations to be evidence of impending or at-risk populations. madness,they may seriouslymisinterpret social events, and they may fail to benefit from treatmentbecause of pressureto concealtheir symptoms. The more frequent occurrenceof paralysis,hypna- Narcolepsy gogic hallucinations, presenceimagery, and nightmar- ish dreaming in personswith narcolepsyis likely due General. During their nocturnal sleep episodes, to the fact that the latter tend more easily to shift people with narcolepsy may experience frequent directly into REM sleep.There is thus greateropportu- dreams that are intense, vivid, and bizarre.211.186Com- nity for the intercalation of dream contentswith wak- pared with those suffering from insomnia, patients ing perceptions.Comparisons between SOREM dreams with narcolepsy report more frightening, recurrent and regular REM dreams of personswith narcolepsy dreams."1 These may become so vivid and realistic would be helpful in elucidating the mechanismsof that the patients confuse dreaming with waking reality, thesehallucinatory processesas well as evaluatingthe incorrectly remember dreams as real events, and de- velop concerns about losing their sanity.l71.187 Although relative impact of these disturbed dreamson daytime such confusions have led to false allegations of sexual functioning and distress. 76.4 ABNORMAL SLEEP

REMSleep Behavior Disorder dreaming. Both disorders-sleep terrors and somnam- bulism-occur in NREM sleep, typically stage 4 sleep RBD occurs primarily in men over the age of 50 early in the night. They have been described as disor- years and is characterizedby excessivemotor activity ders of arousal,203.204or more recently as "partial arous- and dream-enactingbehaviors.l98. 199 (See Chapter 64). aIs,"205because of the autonomic and motor arousal Thesebehaviors are often violent and related to ongo- that propels the patient toward an incomplete wake- ing nightmarish dream content.Patients do not appear fulness. Gastaut and Broughton described the "arousal to enact all of their dreams; just those that involve response" as a state of mental confusion and disorien- themes of confrontation. aggression.and violence. A tation with automatic behavior, nonresponsiveness to "stereotypicnightmare" of pursuit and threat accompa- external stimuli, difficulty in being awakened, retr0- nying RBD episodeshas been described. 1,. It is visually grade amnesia for the episode, and fragmentary or vivid, with motor hyperactivity in both the dreamed absent recall of dreams. Further, the patient appears self and other characters.2IIOAlthough nightmares are to be hallucinating yet displays a waking-like alpha commonly reported by RBD patients, not all patients pattern.206 Despitethis appearanceof dissociatedha.llu- recall etIisodesof overt dream enactment behaviors. cinating, it was thought that the role of dream content SpouseS,however, can infer dream content by observ- in the arousals was minimal.203Later evidence (e.g., see ing the movementsof RBD patients.2IIO reference 206) suggested that some type of dreaming The theme of pursuit and assault is the most com- may accompany most arousals, even tnough recall for mon typical dream theme reported in our surveys of it is impaired. In extreme casesof so~ with normal and sleep-disorderedindividuals (cited earlier); violence, dream content is often suspected as an imme- it is possiblethat the stereotypeddisturbed dreaming diate cause; indeed, in many cases a macabre night- in RBD is an amplified variation of a normal phenome- mare parallels the violent act. non and not a central pathophysiologicalmechanism of the disorder.Or, it may be that the pervasive threat Sleep Terrors depicted in RBD dreams reflects either the unique physiological substrateof RBD (sudden muscle tone The heart-wrenching screams and terrified facial ex- intrusions into REM sleep)or the menacing psychoso- pressions of a child or adult enduring a sleep terror ciological nature of the disorder (ongoing stress on would prompt a naive observer to conclude that some family integrity). Studiesof dream content and sleep- fearful dream had triggered the reaction.However, the dream relationshipsare severelylacking. physiologicalcharacteristics of terrors are substantially Oonazepam not only suppressesthe abnormal be- different from those of idiopathic nightmares (Table haviors of REM sleepbut also reducesthe disturbing 66-5) and victims of sleep terrors seldom report that dreams associatedwith them2°1.202; cessation of the elaboratenightmares are the principal causeof their medication is followed by a recurrenceof both abnor- arousal.Many do report cognitive elementsthat seem mal behaviorsand nightmares.2O1 scary enough: glimpses of a monster or strange man, the walls "closing in," and so forth. Over 50%of terror awakeningsmay produce cognitive activity of some Sleep Terrors, Somnambulism, form.206This estimateis surprisingly similar to the esti- and Sleep Violence mate of recall of mental content after awakeningsfrom NREM sleepmore generally.- The mental component Two sleep disorders with similar behavioral and of terrors may thus stem in part from processesalso psychophysiologicalfeatures both implicate disturbed driving NREM dreaming. Fisher et al.21identified two

Table 66-5. DIFFERENTIATIONOF NIGHTMARE DISORDER FROM SLEEPTERROR Nightmare Disorder SI_p Terror

Sleepstage StageREM (or 2) secondhall of night Stages3 and 4 first hall of night Sleepbehaviors Not typical Screaming.bolting. etc. Autonomic activation None to moderate:inaeased heart rate,mild Moderate to extreme: tachycardia, rapid or no inaea.sein respiration.eye movement breathing, sweating density Awakening Fully alert, continuing distress Disorientation. confusion Unresponsive to stimuli Mentation reports Detailed,story-li1ce dreams Absent or fragmentaryimages, dreams in 8OII\e cases Emotions Primarily fear, anxiety.anger or rage.disgust Primarily terror, fear,disgust Return to sleep Sometimesdifficult Usually easy Experimentalelicitation Not clearly established With suddenloud buzzer in somesubjects Complications Insomnia,sleep avoidance, daytime anxiety, Injury to self or other dueto nocturnalbehaviors distress 0REAMINcDJSORDERS 765

, types of terror-associat~ dream contents:(1) imagery and being hurled into the air, among other insults. At occurring simultaneously with or just before the age 25, the patient enacted a dreamed attack by an : arousal.and (2) imagery elaboratedsubsequent to the intruder in his house.He describeshow the behaviors awakeningand associatedwith the visible physiologi- seemedto stem from disturbed dreaming: cal manifestationsof anxiety (e.g., fear of suffocating relatedto sudden respiratory changes). . . . he left the house by running through a screen In many of the reports in Fisheret aL, specifichallu- door, enteredhis automobileand drove 8 kilometersto cinatory contentscould be identified that appearedto his parents' home without an accident,and awakened trigger the terror event.:n For example, one young them by pounding on their door.Z1~) man's recurrent, terrified awakenings were regularly associatedwith imagesof choking, such as swallowing While driving, he remembersbeing awareonly of driv- nails or choking on electrodes.The occurrenceof sucl\ ing to his parents' house to escapean intruder in imagery triggers remains consistentwith the disorder his house. of arousalmodel; the arousaltrigger may be cognitive, He also attempted to stranglehis wife while dream- such as a frightening image, rather than either physio- ing that he was protecting her. According to his wife: logical. such as an apnea.2111 or external,such as a loud buzzer.- It is also possiblethat the relative paucity of He later told me that he was dreamingthat someone dream recall after a terror,is due to retrogradeamnesia was trying to strangleme and so he was trying to pry accompanyingthese awakenings rather than to an ab- the attacker's hands off me. But actually, his hands senceof content per se. It may be that the extreme were wrapped around my neck, while my hands were aroundhiS "hands-trying to pry his handsoff my neck. autonomicactivation of a terror arousaldisrupts short- It was my screamingthat finally woke him up.n! (pH6) term memory to a great extent.Amnesia has also been suggestedto account for lower rates of dream recall This patient showedno personalitydisorder, history from NREM (vs. REM) sleep.- Someatypical casesof of drug abuse,or other pathologiccondition that might terror210demonstrate little disorientation on arousal explain the violence. However, in adult sleepwalkers and dreams with hallucinatory vividness. However, there is psychopathologicevidence suggestive of diffi- relatively little data exist on this question. culties in dealing with aggression.216A variety of other clinical featureshave also been reported,- most nota- Somnambulismand Sleep Violence bly, a DSM-m-R axis n diagnosisof obsessive-compul- sive personalitydisorder in 21% of nonviolent and 50% Somnambulistic actions may be complex, such as of violent nocturnal wanderers.Altered sleephas also dressing or driving a car,211 and may be performed beennoted. Comparedwith controls,young male som- with suostantialdexterity212i more often, however,they nambulists have more stage 3/4 sleep with hyper- are mundane,stereotyped, and accompaniedby amne- synchronous(greater than 10 see and 150 J.LV) delta sia. It is thus difficult to determine the involvement of waves, greater stage 3/4 sleep percentage,and more cognitiveactivities in theseactions. Although somnam- stage 3/4 sleep interruptions.- 213 A subgroup also bulistic episodes-like nightmares-rarely occur in the demonstratestheta waves prior to wandering.- One laboratory,2OI.21J questionnaires in combination with seriouslyviolent group revealedless alpha activity and ambulatoryrecorders have beenuseful in eliciting brief lowerlevels of stage3/4 sleep comparedwith nonvio- imagery reports.Some reports are nightmarish, for ex- lent somnambulists or healthy controls.217Although ample, "someonebreaking in:' "stones shattering my age may explain some disaepant findings for NREM window," "ceiling falling on bed," "earthquake with sleep, it remains unknown whether any of these 0b- bed moving," while others are of more commonplace served sleep characteristicsare associatedwith emo- events, for example, "feed the chi1d," "take the dog tional activity, dream content, or measuresof psycho- out." pathology in thesepatients. In more extremecases of somnambulisticviolence, disturbed dreaming is consideredto be a contributing factor.n. Many case reports21'suggest that disturbed DISTURBED DREAMING IN dreaming can playa considerablerole, especially in NEUROLOGICAL CONDITIONS violent incidentsinvolving complexfight-or-ftight reac- tions. Such reactions do suggest that the patient is Global Cessation of Dreaming reacting to a hallucinated -threat. A detailed case studya' illustrates this point. A 43-year-oldman with Changes in the recall of dreams and in their global a benign medicaland psychiatrichistory reported sleep characteristics as a function of neurological illness have behaviorsarising at age5 and continuing to the present been appreciatedever sinceCharcot211. 219 first reported (frequency:five to seven per week). Thesewere often on a patient with complete loss of visual imagery, violent excursions&om the bed, with complex behav- including loss of visual dreaming. This, and a later iors suggestingnightmares, for example, stabbing at case report of complete cessation of dreaming by Wil- furniture or the air with knives, swinging and throwing brand,%10 stimulated a great deal of interest in dream baseballbats, running out of the house. He had suf- disturbances under the nosological heading of Charcot- fered numerouslacerations, ecchymoses, and sprained Wilbrand syndrome.l53 In more recent times, interest ankles; his wife had suffered bruises, strangulation. has been focused on global cessationof dreaming(GCD). 766 ABNORMALSLEEP

Solms'sl534-year empiricaI investigation of dream tions in their dreams than do controls231;they also have changesin neurologicalillness revealedthat of the 361 less varied emotions, with a lower frequency but a neurological patients seen during this period, 93.4% higher intensity. AlthouJdl both medicated and non- had undergonea changein someaspect of their dream medicated patients have higher REM densities than do experienceas a function of their condition. Further, controls, medicated patients describe their dreams as 34.9%of the 321queried about GCD reported that they being more vivid than do the other groups. had ceaseddreaming altogether since the onsetof their The role of the temporal lobe is demonstrated even illness.Parietal lobe involvement significantly differen- more spedfica1ly by tlie occurrence of repetitive, pain- tiated patients with and without GCD; 42% of GCD ful dream imagery. Case studies153-23Z indicate that epi- patients had parietal lesionsand an additional 7% had leptic auras may be incorporated into recurrent noctur- lesions in closeproximity to parietal lobe ("periparie- nal dreams and that recurrent dream themes may, in tal"). Parietal involvement in dream recall confirms turn, appear in the "dreamy state" of a temporal lobe findings from a previous study on fewer patients.221 complex partial seizure. REM sleep anomalies, such as Solms also found that the presenceof frontal lobe le- rhythmical temporal epileptiform activity, have also sions characterizedsome patients (8%) with GCD, in- been documented.23ZSolms1S3 found a 7.9% (out of 114) dependentof parietal lobe involvement.153This is con- incidence of. recurring nightmares in his neurological sistentwith the reduceddream recall seenafter frontal sample: five of these presented with definite epilepsy; lobotomy amongschizophrenic patients222 but not with in two others it was suspected. In six of the seven a study221finding no such connection.The 43%of GCD cases, limbic system involvement could be demon- casesnot linked to either parietal or frontal lesionsall strated with no evidence of hemispheric predomi- had diffuse and nonlocalizablelesions. nance. Whether there is latera1izationof neurological dam- agein GCD is at presentuncertain. Equal distributions of right- and left-sided lesionswere found in 45 of 47 Dream-Reality Confusions cases,153whereas the left inferior mesial occipitotemp- oral cortex has also been implicated.221The latter is associatedwith a syndrome(including right homony- Intensification and vivification of dreaming to the mous hemianopia,alexia without agraphia, visual as- point of confusion with reality has been described as characteristic of a small (5.3%) subgroup of neurologi- sociative agnosia) which is typically explained as a cal patients (N = 189)153and is illustrated bv the follow- disconnectionbetween right hemispherevisual proc- essesand left hemispherespeech processes. This notion ing example.A 32-year-oldright-handed 'woman sus- is consistentwith the reduced dreaming after corpus tained an opel} skull fracture when a rioter threw a callosotomyand in agenesisof the corpus callosum.223 brick through her car window: Our finding of relatively intact dreaming following right hemispherectomy224but extremely impoverished This patient reported that in the first weeks after her recall following left hemispherectomy225also clearly injury she experienced frequent and vivid nightmares, which, although bizarre, were very much more realistic supports a left hemispherelateralization interpretation than her normal dreams. She had always been a vivid for GCD. Neuropsychological reviews226.227 favor a pre- dreamer but she experiencedthese dIeams as being dominant role for left hemisphereprocesses in dream "utterly different" She felt that her dream recall was generationmore generally. greatlyenhanced, and shestated that shehad consider- Other conditions are known to suppressdream re- able difficulty convincingherself that the dreamswere calL although not to the extent of GCD. In chronicbrain not real . . . the dreamswere always unpleasant. . . syndrome,dream recall from REM sleepdeteriorates as one night that there was somethingwriggling about in the illness progressesfrom mild (57%recall), to severe her "knickers," so she put her hand down and found (35%),to aged and severe(8%).228 In Korsakoff's psy- (to her extreme horror) a green snake. She then felt chosisdue to alcoholism,near-normal REM sleeptime somethingelse was there and discoveredthree smaller snakes.Finally a black snakecrawled up into her va- (29.4%)is seen.but poor dream recall (3%).229Patients gina. She awoke in terror and searchedthe bed for with permanentamnesia for recentevents due to mild snakes.. . . On other occasionsshe would awake from encephalitis also have impoverished dreaming; their dreams and feel compelled to check all around the reports are less frequent than normal (28% vs. 75% of house. WC,l92) REM awakenings),and simpler, nonsymbolic, repeti- tious, stereotyped,and lacking in emotions and day The patient's dreams returned to normal within 2 residues.230 months of the assault. There is someevidence consistent with the hypothe- sis that dream-reality confusions are due to localized Epilepsy anterior limbic lesions.However, there is no one spe- cific pattern of lesionswithin this region that is selec- Disturbancesof emotionalfunctioning in the dreams tively associatedwith the symptom; equal numbers of epilepsy patients are clearly consistentwith limbic of casesshow lesions in the medial prefrontal cortex, system participation in the organization of dreaming. anterior cingulate gyrus, basal forebrain nudeL and Patients with temporal lobe epilepsy who are awak- anteromedial diencephalic nuclei. The most severe ened from REM sleep present more unpleasant emo- casesalso involve medial frontal cortex. DREAMINGDISORDERS 767

. Vivification of dream reality occursoften in a num- and at other times secondary associated symptoms , ber of other disturbancesin which brain damageis not (e.g., narcolepsy).Often, REM sleep fragmentationor necessarilya contributing factor. For example, dream- REM sleep intrusion at the sleep-wake transition is reality confusions are well-known in SP and narco- implicated in disturbed dreaming. However, some .lepsy171(see above). They also occur in psychotic indi- dreaming disturbances are also frequently seen in viduals and were noted as early as 1911by Ellis to NREM sleep disorders such as somnambulism.Most occur in casesof fatal heart disease,hysteria, " some disturbances remain poorly understood because of forms of insanity," and "disordered cerebraland ner- their intractability to laboratory study and becausepa- vous conditions."233(p237)Indeed, dream-reality confu- tients are reluctant to report them in clinical settings. . sionscan occur in normal personsas a result of dream Nevertheless, effective treatments are available for vivification-what has beenreferred to as realitydream- many common disturbancesand other treatmentsare . ing.l65Among the many types of reality dreams are presentlyunder development. flying dreams, lucid dreams, sexual dreams, urination dreams, and dreams with incorporation of various or- ~ ganicsensations (e.g., pain. hunger). References

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Sleep. 1999; 1998;21(suppl):286. 22(suppl):SI7S. ~ trN!- IV uJ >-l- /CJ/,/ 2~ PRINCI PLES 'ij AND ~ .1, PRACTICEOF

eep. .

I I I ed cine I THIRD EDITION I

Meir H. Kryger, MO, FRCPC Director, SleepResearch St. BonifaceGeneral Hospital ResearchCenter Professorof Medicine University of Manitoba Wmnipeg, Manitoba, Canada

Thomas Roth, PhD Head, Division of SleepDisorders Medicine Henry Ford Hospital Clinical Professorof Psychiatry University of Michigan Detroit, Michigan William C. Dement, MO, PhO Lowell W. and JosephineQ. Berry Professorof Psychiatry and BehavioralSciences and Director, SleepDisorders Center Stanford University Schoolof Medicine Stanford,California

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