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