18818ournal ofNeurology, Neurosurgery, and Psychiatry 1997;62:188-192 A controlled study of sensory tics in Gilles de la J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.62.2.188 on 1 February 1997. Downloaded from Tourette syndrome and obsessive-compulsive disorder using a structured interview Kit-Yun Chee, Perminder Sachdev Abstract Keywords: Gilles de la Tourette syndrome; obsessive Objective-To determine the prevalence compulsive disorder; structured interview; sensory tics and characteristics of sensory tics in the Gilles de la Tourette syndrome (GTS), (T Neurol Neurosurg Psychiatry 1997;62:188-192) and a matched population ofpatients with obsessive-compulsive disorder (OCD) using a structured assessment. Introduction Methods-50 subjects each of GTS, OCD, The Gilles de la Tourette syndrome (GTS) is a and healthy controls were studied to neuropsychiatric disorder characterised by the determine the prevalence and phenome- presence of multiple motor tics and at least nology of sensory tics, and diagnose tic one vocal tic.' It is now widely recognised that disorders, OCD, and affective disorders GTS is more complex than the above defini- according to DSM-III-R criteria. The tion implies, and there is evidence that obses- severity of tics and obsessive-compulsive sive-compulsive disorder (OCD) is an symptoms were quantified using the important comorbid condition2 7 that may be Tourette syndrome global scale (TSGS) genetically linked to GTS.5 and Yale-Brown obsessive-compulsive Bliss et al' recently kindled interest in an scale (Y-BOCS) respectively. area which had hitherto received little Results-The GTS group (28%) had sig- attention, when they described Bliss's own nificantly greater life-time prevalence of "sensory" tics in the context of a 62 year sensory tics than the OCD (10%) and history of GTS. Since then, four systematic healthy (8%) groups (P < 0.05). The sen- studies of this symptom have been sory tics in both the GTS and OCD published.1'0 ' Of these, only two used direct groups were predominantly located in interviews,'012 and none of the studies was rostral anatomical sites. Multiple sensory controlled. The inclusion of a healthy control tics occurred in some patients with GTS population is important because the phenom- or OCD, but not in healthy subjects. ena described are subjective and therefore Neuropsychiatric Within the OCD group, those who had Institute, The Prince sensory tics had significantly higher difficult to characterise as pathological with certainty. In addition, as far as we are aware, SchoolofPsychiatry TSGS scores (P < 0.0001), and a higher the presence of sensory tics in OCD has not University of South prevalence of GTS (P < 0-005). http://jnnp.bmj.com/ Wales, Sydney, Conclusions-Sensory tics seem to be a been examined, and has the potential of increasing our understanding of the complex K-YAChee common and distinctive feature of GTS links between GTS and OCD. P Sachdev and that subpopulation of patients with An examination of the medical literature Correspondence to: OCD predisposed to tic disorders. Dr P Sachdev, Neurophysiologically, a possible explana- discloses considerable variation in the nosol- Neuropsychiatric Institute, ogy and definition of these sensory experi- Prince Henry Hospital, PO tion for sensory tics is that they represent Box 233, NSW ences. Table 1 summarises this. We defined Matraville, the subjectively experienced component sensory tics as somatic sensations which were: on October 4, 2021 by guest. Protected copyright. of neural below the threshold ReceivedReeied225MaytrMay1996.1996 dysfunction (a) transient and recurrent, (b) experienced at Accepted 13 August 1996 for motor and vocal tic production. or close to the skin, (c) readily localisable by the patient to a particular part of the body, and recognised as stereotyped and unusual, (d) experienced with or without an associated motor or vocal response, and (e) experienced Table 1 Nosology and definitions of sensory tics as described in the published in the absence of obvious physical pathology. literature Specifically, we excluded "urges" from sensory Symptoms Motor or vocal tics because: (1) An "urge" is a drive that included response to often precedes a behavioural response (in this Author Nosology in definition sensation required case, a tic), although the behaviour may be Bliss et al 1983" Sensory Urge No consciously suppressed. It is therefore a experiences Somatic sensations Shapiro et al 1988" Sensory tic Somatic sensations Yes cognitive rather than a sensory experience. (2) Kurlan et al 19891 Sensory tic Somatic sensations Yes Even when patients describe an urge in a body Psychological experiences Cohen and Leckman 1992'2 Sensory phenomena Urge No part (rather than in the mind), they do not Somatic sensations localise it close to the skin, and do not equate it Heightened sensitivity Impulsivity with a somatic sensation. (3) Most patients Leckman et al 199313 Premonitory urge Urge Yes with GTS report that, at least some of the , *-- Somatic sensations No Present--. study*,Sensoryi tic--- time, their tics are preceded by a conscious A controlled study ofsensory tics in Gilles de la Tourette syndrome and obsessive-compulsive disorder using a structured interview 189 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.62.2.188 on 1 February 1997. Downloaded from urge. Furthermore, we defined motor and Table 2 Demographic and clinicalfeatures-a vocal tics as repetitive, stereotyped move- comparison ofgroups ofpatients with healthy controls ments, behaviours, or vocalisations, preceded GTS OCD Healthy at least sometimes by a conscious urge, per- (n = 50) (n = 50) (n = 45) formed as an end in itself and experienced as Age (mean (SD)), 20-8 (10-8) 31-2 (13 3) 20 7 (5 3) irresistible but suppressible. Sex MP/F 40/10 29/21 22/23 TSGS score:, Mean 23-0 1.2 0 0 Methods Median 23-0 0.0 0.0 We recruited 50 patients with GTS, who met Range 1 5-56 7 0 0-27.8 0.0 DSM-III-R criteria, by contacting patients Y-BOCS score:d previously seen at the Neuropsychiatric Mean 5 6 18 2 0.1 Median 0.0 18-0 0.0 Institute and advertising through the Tourette Range 0 0-29 0 0-0-34 0 0 0-6-0 Syndrome Association of Australia. In addi- tion, we recruited 50 patients with DSM-III-R GTS = Gilles de la Tourette syndrome; OCD = obsessive- compulsive disorder; TSGS = Tourette syndrome global diagnosis of OCD from three hospitals in scale; Y-BOCS = Yale-Brown obsessive-compulsive scale. Sydney, and from OCD support groups. a'The OCD group was older than the healthy group (t = 4-95, df = 93, P < 0-0001). Because it is possible for GTS and OCD to bThere were more males in the GTS than the healthy group co-occur in a patient, we used the U2 = 9 8, df = 1, OR 4 3, P < 0 005). following 'GTS v healthy; Mann-Whitney U = 0, W = 1035-0, guidelines in assigning a subject to a primary p < 0 0001. category of GTS or 'OCD v healthy; Mann-Whitney U 877-5, W = 1912 5, OCD: (1) the primary dis- p < 0*001. order was the one which had the most promi- dGTS v healthy; Mann-Whitney U = 694-0, W = 17290, nent p <0-0001. symptomatology in the previous year, dOCD v healthy; Mann-Whitney U = 48-0, W = 1083 0, and whose symptoms (tics v obsessions-com- p < 0-0001. pulsions) produced the greater distress or dis- ability and had brought the patient to medical attention; (2) both investigators independently Results agreed on the primary diagnosis; and (3) an Table 2 gives the demographic and clinical independent psychiatrist concurred with the features of the three groups. The GTS group assignment. All patients with GTS and OCD had significantly more males, and the OCD could be assigned on these guidelines without group was significantly older than the healthy dispute. Fifty healthy controls, who were vol- group. The implications of these differences unteers with no history of GTS, chronic motor are discussed below. The number of subjects tic disorder, or OCD, were recruited from per- below the age of 16 in the GTS, OCD, and sonnel of the Eastern Sydney Area Health healthy groups were 20, 7, and 10 respectively. Service by advertisement. On detailed assess- Both the GTS and OCD groups had higher ment, however, five otherwise healthy controls TSGS and Y-BOCS scores than controls. A had had a lifetime of OCD and these were within group analysis was performed compar- therefore excluded from the analyses. We ing hospital to support group ascertained sub- excluded subjects with active psychoses, jects in the GTS and OCD groups according significant head injury, other neurological to age, sex ratio, severity of primary symp- disorders, and drug or alcohol misuse. To toms, and the prevalence of sensory tics. The improve the accuracy of reports elicited, we only significant finding was that patients with excluded subjects under the age of 10 and OCD in hospital were older than those from http://jnnp.bmj.com/ interviewed all subjects under the age of 16 in support groups (t = 5-5, df = 48, P < 0-0001, the presence of an adult informant. Informed two tailed). The number of subjects from the consent was obtained from all participants, two patient groups, GTS and OCD, respec- and when appropriate, a parent or guardian. tively, who were on psychotropic medication Subjects were interviewed using a modified in the three weeks before the study was as fol- Yale schedule for Tourette and other behav- lows: 27 and two on antipsychotic drugs, three ioural syndromes.8 This schedule yielded and 32 on antidepressant drugs, nine and DSM-III-R diagnoses for GTS, chronic and none on clonidine, and none and nine on on October 4, 2021 by guest.