NADD Bulletin Volume II Number 1 Article 1

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Comorbidity in Tourette’s Syndrome: Pharmacological Treatment in Adults with a Severe to Profound Handicap

Robert King, M.D.,F.R.C.P.(C)


Tourette’s Syndrome is a neurochemical disorder characterized by frequent motor and phonic tics, a childhood onset with a fluctuating course, a duration greater than one year and associated distress or significant impairment in social, occupational or other important areas of functioning (DSM IV APA, 1994). Negative secondary consequences of the expression of tics (defined in the DSM IV as sudden rapid, recurrent, non-rhythmic, stereotypical motor movements or vocalizations) include impairments in self-esteem and in the establishment and maintenance of interpersonal relationships, impairment in learning and vocational settings and the development of problems in family functioning (Harris, 1995).

Tourette’s Syndrome has an established prevalence of .3 - .5 per thousand in a non-cognitively impaired population (Robertson, 1989). Although its prevalence has not been studied systematically in adults with developmental disabilities, particularly in individuals with severe to profound cognitive impairments, published case reports and case series to date have both recognized the existence of Tourette’s Syndrome in this population and have emphasized the likelihood that this syndrome is currently under-diagnosed (Golden and Greenhill, 1981; Goldman, 1988; Crews et al., 1993; Zarkowska, 1989).

Interpersonal aggression, self-injurious behavior, over-activity and sleep disturbances are frequent concerns of family members and primary caregivers seeking psychiatric consultations to address the mental health needs of adults with severe to profound cognitive impairment. These challenging behaviors are also frequent initial presentations of Tourette’s Syndrome and the multiple psychiatric disorders with which it shares comorbidity. Conditions which frequently occur comorbidly with Tourette’s Syndrome include; Obsessive Compulsive Disorder (OCD) (Leckman, James F. et al., 1994), Attention Deficit Disorder with Hyperactivity (ADHD) (Matthews, 1988), sleep disorders (Robertson, 1988), and self-injurious behavior (Robertson et al., 1989).

The diagnosis of Tourette’s Syndrome requires the presence of motor and phonic tics at some time during the illness. Tics are commonly classified as simple or complex, according to the degree of muscle group involvement when the tic is expressed. The phenomenology and natural history of this disorder, in a non-cognitively impaired population and the natural history of comorbid disorders have all been well characterized (Comings, 1990).

In a developmentally disabled population, however, clinical experience rather than published literature, guides the current challenge of establishing a provisional diagnosis of Tourette’s Syndrome and its comorbid conditions. The diagnostic process is often complicated by the presence of stereotypic behaviors (rhythmic whole body movements or object manipulations) and tardive dyskinesia (repetitive, involuntary, less rhythmic, often oral facial movements occurring as an adverse affect of exposure to neuroleptic medication) (Bodfish et al., 1996).

The topography of self-injurious behavior demonstrated by individuals of average intelligence, has been reported to resemble that demonstrated by a severely cognitively impaired population (Robertson, 1989). Noting a correlation between rating scale measurements of obsessionality, hostility and self-injurious behavior, Robertson has hypothesized that “certain, self-injurious behaviors in GTS [Gilles de la Tourette Syndrome] undoubtedly stem from self-destructive obsessions” (Robertson, 1989, pg. 621). This hypothesis can be extended to consider that some self-injurious behavior in individuals with cognitive impairments who carry a diagnosis of Tourette’s Syndrome, may represent compulsive behavior occurring as a symptom of a comorbid OCD. Anti-compulsive pharmacological interventions (selective serotonin reuptake inhibitors [SSRI’s] and/or Clomipramine) theoretically may decrease the frequency and intensity of self-injurious behavior in this context.

Complex motor tics may result in movements such as touching others, the smelling of objects, retracing steps, twirling, hitting and striking. Theoretically, self-injurious behavior could also occur when an individual with Tourette’s Syndrome experiences a complex motor tic. In a nonseverely cognitively impaired population, the distinction between compulsive behavior and complex motor tics can be guided by verbal descriptions of premonitory urges preceding tics (Lang, 1991) or obsessions (intrusive thoughts, ideas, images or impulses recognized by the individual as irrational and associated with anxiety, which is temporarily relieved by the performance of a compulsive behaviour) (Leckman, 1995). Targeting tics pharmacologically, particularly with Risperidone (an atypical neuroleptic with both dopamine and serotonin antagonistic properties) (Bruun, 1996) and Clonidine (an alpha adrenergic agonist) in cognitively impaired individuals with Tourette’s Syndrome may result in a decrease in the frequency and intensity of self-injurious behavior. In addition, anecdotal reports of decreased frequencies of aggression have been reported with Risperidone (Sandor, 1995). The positive effects which Clonidine can have upon aggression, impulsivity, over-activity and sleep are also well documented (Comings, 1990).

Exploring the potential continuum which may exist between complex motor tics, compulsions and self-injurious behavior, after a careful multidisciplinary diagnostic assessment, can result in successful outcomes to these pharmacological approaches. This will be illustrated in the following case report and abbreviated case series.

Case Presentation

The following case study and tabulated case series represent individuals with severe to profound developmental disabilities referred for the assessment of aggression and self-injurious behavior to the Developmental Disabilities Program of the North Bay Psychiatric Hospital in North Bay, Ontario, Canada. This program provides psychiatric consultations to adults with developmental disabilities in a large, often rural and remote geographical area in Northern Ontario. This program is based upon a bio-psychosocial model which emphasizes a collaborative approach between the consulting psychiatrist and community support networks. Primary care-givers and family members are invited to participate with the consulting psychiatrist to develop a comprehensive approach both to the establishment of a diagnostic hypothesis as well as methods of monitoring the efficacy of proposed treatments.

TN is a 31 year old single female, currently living with a married sibling and supported through a Family Associate Home Program affiliated with an area Association for Community Living. The youngest of 19 children in a blended family, TN was born to a mother who had a history of epilepsy and was maintained on anticonvulsants during her pregnancy. Multiple congenital anomalies were documented at TN’s birth. These include a bilateral incomplete cleft lip and palate, underdeveloped toes and pulmonary hypoplasia. The development of a postnatal seizure disorder has also been documented. A previous psychiatric assessment in 1988, had identified a five year history of hyperactivity, interpersonal aggression and school refusal. At the time, an Axis I, DSM IV diagnosis was not established. Chlorpromazine, a sedating neuroleptic, and Oxazepam, a benzodiazepine were prescribed and maintained until just prior to TN’s presentation to the Developmental Disabilities Program. In 1989, a psychological assessment had noted that “she is very routine oriented and becomes easily upset if there are delays or changes in her daily activities or if she is not instantly gratified”. It was also noted that she was fastidious about details and had certain behavioral idiosyncracies “where she will smile and frown in quick succession, pick at her fingers, pull her hair back several times in order to clear her view, repeat phrases such as `hello’, `no like swimming’, `like school’ and stand up next to her father when he is talking with others and tap him on the arm and shoulder area”. Measurements of adaptive behavior had established a functional age equivalent of approximately 2 years 11 months at this time. It was also noted that TN engaged in self-injurious behavior characterized by continuous finger movements of both hands (causing open sores and bleeding) which increased when she was agitated, excited or left alone and decreased when distracted or relaxed. Her socially offensive behavior was noted to be “most evident when she stands too close to people and touches them inappropriately”. Presenting symptoms to the Developmental Disabilities Program included: extreme agitation, aggressive behaviour towards others and behavioral outbursts.

A review of previous psychological assessments and the observations of current care-givers was conducted. It was noted that TN was described as “always on the go” and “challenged by transition times at her work place”. She was observed to demonstrate an increase in compulsive behaviours when agitated. When questioned, her caregivers did not believe there was an initial obvious correlation between the interruption of her observed compulsive behaviours and her intermittent aggression.

On mental status examination, TN demonstrated a moderate degree of dysarthria which complicated her ability to communicate verbally. Throughout the interview she demonstrated a significant degree of psychomotor agitation. A number of phonic and motor tics were noted. These included throat clearing, a hoarse grunting sound, eye blinking and facial grimacing. She was also noted to engage in a stereotypical knitting motion of her fingers. She demonstrated a broad, appropriate affect and was able to express appropriate affection towards her caregivers. Her caregivers were asked to complete a Yale Global Tic Severity Scale (Leckman et al., 1989). Tics were reported in each of the four categories of this scale. Tics were described as both being frequent and intense, causing a marked functional interference and impairment in her life. Completion of a Compulsive Behavior Checklist (Gedye, 1992) demonstrated the presence of 12 compulsive behaviors occurring in each of the five categories in this scale (ordering, completeness, cleaning and tidying, checking and touching and deviant grooming).

A provisional diagnosis of Tourette’s Syndrome with a comorbid OCD was established. It was felt that her oppositional behavior was occurring in the context of Tourette’s Syndrome. It was also hypothesized that some of her aggression may be occurring in the context of compulsive behavior being interrupted by caregivers. The differential diagnosis included the possibility that she also had a comorbid ADHD.

Clonidine was initially recommended to target her aggression and decrease her tic frequency. This was monitored with a time sampling method. A maximal dose of .15 mg four times a day failed to decrease tic frequency over five months, but significantly decreased the frequency of aggression, allowing an initial decrease in her maintenance dose of Chlorpromazine and the discontinuation of Oxazepam. The addition of Risperidone, beginning at a dose of 1 mg twice a day and increasing to 3 mg twice a day over a two week period, decreased her tic frequency but appeared correlated in time with an exacerbation of compulsive behaviors. Risperidone was discontinued and a trial of Paroxetine at a maximal dose of 20 mg twice a day resulted in improved compulsive behaviors, but an increase in the frequency of aggression initially. After decreasing the dose to 20 mg per day to address the possibility that her increased aggression was related to Paroxetine induced akathisia, the noted improvement in her compulsive behavior was maintained and the previously noted improvement in the frequency of her aggression was re-established. This drug trial occurred concurrently with the implementation of a behavior intervention which targeted verbal perseveration emphasizing an approach based upon an understanding of the functional significance of the verbal perseveration. Ultimately, a 50% reduction in the maintenance dose of Chlorpromazine was achieved, theoretically offering her a decreased risk of the development of tardive dyskinesia.

The following table summarizes this case as well as two additional cases in which various combinations of Clonidine, Risperidone and SSRI’s were utilized to treat individuals with severe to profound handicaps with Tourette’s Syndrome and comorbid conditions

Note:imp-improvement fimp-further improvement nfi-no further improvement det-deteriorated nc-no change


These case presentations support previous hypotheses that self-injurious behavior in an individual with Tourette’s Syndrome can represent motor tics and/or compulsions and can be addressed with a rational pharmacological approach. Clinical case experience of the author, suggests the following guidelines in the diagnostic and treatment phases of this process.

Assessment Phase

1.Utilization of caregiver and family completed questionnaires can be a valuable guide to retrospectively identify the presence of simple or complex phonic or motor tics in cognitively impaired individuals presenting with interpersonal aggression, self-injurious behavior, over-activity or sleep disturbances.

2.The establishment of a diagnosis of Tourette’s Syndrome can then lead to the exploration of other potential comorbid disorders. Oppositional behavior arising in the context of Tourette’s Syndrome, impulsivity in the context of a comorbid ADHD, and the interruption of compulsive behaviors in the context of comorbid OCD, can all be underlying etiologies of presenting interpersonal aggression and/or self-injurious behavior.

3.Particular attention should be paid to previous observations which have documented the absence of “identifiable antecedents” to self-injurious or aggressive behavior. This may well be a clue to the presence of involuntary tics or anxiety-generating obsessions that can not be verbally expressed by the individual concerned.

4.It is important to distinguish stereotypic behavior and signs of tardive dyskinesia from complex motor tics. A review of previously prescribed medication, in particular neuroleptics, is often helpful in this respect. A videotape analysis of these movement disorders can be invaluable.

Treatment Phase

1.Incorporating the perspective of primary caregivers and family members in identifying the presenting symptom of greatest functional significance is a critical step in decision-making regarding which drug to initially implement.

2.It is important to have reasonable expectations of improvement to be gained from pharmacological interventions when targeting tic frequency and the frequency and intensity of compulsive behavior. Mild to moderate improvement, however, may create an opportunity for a renewed functional behavioral analysis and creative behavioral and habilitative interventions.

3.Risperidone has shown initial promise in reducing tic frequency in the absence of the significant side effects often associated with traditional antipsychotic medication. It is important to allow sufficient time to judge its efficacy with respect to reducing tic frequency and targeting interpersonal aggression. It may require a duration of at least three months to objectively determine Risperidone’s efficacy (Remington, 1994). While observing its potential to suppress tics, it is important to be aware Risperidone has the potential to increase compulsive behaviour and subsequently interpersonal aggression (Remington, 1994).

4.Clonidine can successively decrease impulsivity occurring in individuals with Tourette’s Syndrome. This can occur even in the absence of a suppression of tic frequency. It can also be of benefit in targeting initial insomnia. Clonidine has been safely prescribed in conjunction with Risperidone.

5.SSRI’s are generally well tolerated in severely cognitively impaired individuals. They have the potential to decrease aggression occurring in the context of OCD. However, a minority of individuals prescribed SSRI’s experience akathisia and insomnia. There is a potential for increased aggression occurring in the context of akathisia to be misinterpreted as a response to other environmental variables and/or attributed to the natural history of the underlying disorder.

6.The rational use of combinations of SSRI’s, Clonidine and Risperidone in treatment of Tourette’s Syndrome and its comorbid disorders can create opportunities to:

a)reduce and potentially discontinue maintenance doses of neuroleptics thereby reducing lifetime exposure to these medications and the risk of tardive dyskinesia

b)taper and reduce benzodiazepine doses, thereby reducing the dependency liability and decreasing the sedative impairment which this class of medications may have upon habilitative programming.

The rational use of these medications in Tourette’s Syndrome is strengthened by recent work addressing the potential etiologies of Tourette’s Syndrome and its comorbid conditions. A variety of etiologies (genetic, autoimmune responses to infections, pre and postnatal insults as well as others) have been identified as potentially contributing to neurochemical and structural alterations in the region of the basal ganglia and prefrontal cortex in these disorders. Further work in this area will undoubtedly lead to more specific therapeutic interventions. In the interim, it is hoped that the above guidelines will be of assistance in developing rational and safe approaches to the pharmacological treatment of cognitively impaired individuals with Tourette’s Syndrome and its comorbid conditions.


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For further information contact:

Robert J. King, M.D., C.C.F.R.P., F.R.C.P.
North Bay Psychiatric Hospital
Highway 11N, P.O. Box 3010
North Bay, Ontario P1B 8L1, Canada