Comorbidity in Tourette Syndrome: lifetime prevalence and risks
Finally we have a study that provides us with some analysis of comorbidity in Tourette Syndrome (TS) based on a large sample size.
The Tourette Syndrome Association International Consortium for Genetics has published a report that looked at lifetime prevalence, clinical associations, ages of highest risk, and etiology of psychiatric comorbidity in 1,374 individuals with TS who were compared to 1,142 TS-unaffected family members.
Some of the key findings include:
- The lifetime prevalence of any psychiatric comorbidity among individuals with TS was 85.7%;
- 57.7% of individuals with TS had 2 or more psychiatric disorders.
- 72.1% of individuals with TS met DSM-IV-TR diagnostic criteria for OCD or ADHD.
- Other disorders, including mood, anxiety, and disruptive behavior, each occurred in approximately 30% of the participants.
- The age of greatest risk for the onset of most comorbid psychiatric disorders was between 4 and 10 years, with the exception of eating and substance use disorders, which began in adolescence.
- TS was associated with increased risk of anxiety and decreased risk of substance use disorders independent from comorbid OCD and ADHD; however, high rates of mood disorders among participants with TS (29.8%) may be accounted for by comorbid OCD.
- Parental history of ADHD was associated with a higher burden of non-OCD, non-ADHD comorbid psychiatric disorders.
- Genetic correlations between TS and mood, anxiety, and disruptive behavior disorders may be accounted for by ADHD and, for mood disorders, by OCD.
Looking at their findings, there’s really nothing surprising in the rates of comorbidity nor the possibility that some comorbidity may be better accounted for by the presence of ADHD or OCD than by TS itself.
Hirschtritt ME, Lee PC, Pauls DL, Dion Y, Grados MA, Illmann C, King RA, Sandor P, McMahon WM, Lyon GJ, Cath DC, Kurlan R, Robertson MM, Osiecki L, Scharf JM, Mathews CA; for the Tourette Syndrome Association International Consortium for Genetics. Lifetime Prevalence, Age of Risk, and Genetic Relationships of Comorbid Psychiatric Disorders in Tourette Syndrome. JAMA Psychiatry. 2015 Feb 11. doi: 10.1001/jamapsychiatry.2014.2650. [Epub ahead of print]