Megan Brooks

June 23, 2010

June 23, 2010 (Buenos Aires, Argentina) — Anxiety/panic disorder is the most functionally disabling comorbidity in adults with Tourette's syndrome (TS), according to research presented at the Movement Disorder Society 14th International Congress of Parkinson's Disease and Movement Disorders.

"Although tics wane in the majority of TS patients during or after adolescence, those patients who have clinically significant persisting tics in adulthood are at risk for psychosocial and occupational disability that is related directly to their tic disorder," study presenter David G. Lichter, MD, professor of clinical neurology at the University of Buffalo School of Medicine and Biomedical Sciences in New York, noted in an email to Medscape Neurology.

In this study, they report that although obsessive-compulsive disorder (OCD) was the most common psychiatric comorbidity, global function appeared to be most affected by the presence of anxiety/panic disorder, which was also closely linked to substance abuse disorder.

"Psychiatric comorbidities should be screened for, monitored closely, and treated aggressively" in adult TS patients, Dr. Lichter said.

Global Functioning Worse With Greater Tic Severity

To determine the relative importance of tics and psychiatric comorbidities to global functioning, Dr. Lichter's group followed up 66 adults with TS (45 men and 21 women) for an average of 8.2 years. Their average age was 36.9 years; 65.2% were undergoing a neuroleptic therapy, 50.0% were undergoing serotonin reuptake inhibitor therapy, and 7.6% were taking a stimulant medication.

Of the 66 subjects, 21 (31.8%) had a diagnosis of moderate or greater OCD defined as a Clinical Global Impression (CGI) scale score of 4 or greater, whereas 41 (62.1%) displayed borderline or mild OCD behavior (CGI score of 2 or 3). Nineteen (28.8%) had at least moderate anxiety/panic disorder on the CGI scale, whereas 8 (12.1%) had borderline or mild anxiety.

Other TS-associated conditions included depression (16.7%), depressed mood (12.1%), bipolar disorder (12.1%), rage attacks and severe self-injury behavior (each 4.5%), history of childhood attention-deficit/hyperactivity disorder (33.3%), residual adult attention-deficit disorder (18.2%), substance use disorder (22.7%), and psychosis and restless legs syndrome (1 subject each 1.5%).

Overall, the mean score on the 100-point Global Assessment of Functioning scale was 65.8, which, according to the scale, is indicative of "some mild symptoms or some difficulty in social, occupational, or school functioning, but generally functioning pretty well; has some meaningful interpersonal relationships."

"Tic severity was the clinical variable most closely correlated with global functional disability," Dr. Lichter noted, with motor tics being more disabling overall than vocal tics.

Two-thirds of the patients had moderate or greater overall impairment caused by their tics as rated by the Yale Global Tic Severity Scale; "their tics were associated with clear (or in some cases major) problems in self-esteem, family life, social acceptance, or job functioning," Dr. Lichter reported.

Comorbid Psychiatric Conditions

The study authors found a variety of comorbid psychiatric disorders that contributed to functional disability. The most important of these were anxiety/panic disorder and bipolar/rage disorder, both of which were strongly associated with substance use disorder. "The latter may include not only drugs, which may ameliorate tics, such as marijuana and benzodiazepines, but also cocaine, which may markedly aggravate tics."

Substance use disorder, note Dr. Lichter and colleagues, "has been underrecognized as an important correlate of interrelated psychiatric comorbidity in adult TS and adversely impacted the clinical course and global functioning of 23% of our subjects."

There was a weaker association of functional disability with OCD. Although OCD behaviors were present in most study subjects, they produced functional impairment relatively infrequently (17% of patients).

A history of depression or depressed mood was not a predictor of global functional status in the cohort, which was somewhat surprising, according to researchers. However, the fact that none of the patients in the series was severely depressed is a possible explanation for this finding, Dr. Lichter said.

"Less severe forms of depression were seen in some of our patients and may have affected quality of life in these subjects but were insufficient to significantly affect psychosocial or occupational functioning when the group as a whole was considered," he explained.

Dr. Lichter and colleagues note that the relatively small patient population, possible referral bias, and reliance on CGI scales alone to assess severity of psychiatric symptoms other than OCD are limitations of the study.

Results of "High" Importance

In an email to Medscape Neurology, Barbara J. Coffey, MD, MS, director of the Tics and Tourette’s Clinical and Research Program, New York University Langone School of Medicine, in New York City, said she was "very interested to hear about Dr. Lichter’s work, especially since this is with adults."

"These results," she said, "are not at all surprising to me and will be of high importance to clinicians. We have reported similar findings of elevated rates of non-OCD anxiety disorders in our TS child and adolescent patients and correlation between anxiety disorders and tic severity, which impact quality of life." Dr. Coffey was not involved in the study.

Dr. Lichter and Dr. Coffey have disclosed no relevant financial relationships.

Movement Disorder Society (MDS) 14th International Congress of Parkinson's Disease and Movement Disorders: Abstract 1037. Presented June 17, 2010.

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