March 16, 2015, by Charlotte Beer
Tourette’s Syndrome and the likelihood of experiencing other psychiatric disorders
Young people with Tourette’s Syndrome (TS) their parents and clinicians are all aware of how often TS is accompanied by other disorders such as Attention Deficit Hyperactivity Disorder (ADHD) and Obsessive-Compulsive Disorder (OCD). Until recently evidence to support this idea has come mainly from small studies and anecdotal evidence. A recently published study (February 2015: see details below) provides important evidence about the possibility of experiencing a co-morbid condition in what the authors claim is the largest study of its kind to date.
The findings show that in a study of 1374 participants with TS and their TS-unaffected family member (n=1142) almost 86% of participants with TS will be diagnosed with a further psychiatric disorder during their lifetime. Moreover, nearly 58% will receive two or more diagnoses. Although rates of ADHD (54%) and OCD (50%) were highest, rates for mood disorders, anxiety disorders and oppositional defiant or conduct disorder all reached nearly 30%. Analysis of the TS-unaffected family members provided evidence for the genetic relationship between TS, OCD and ADHD.
The implications of these findings are that the high burden of psychiatric disorders these young people and their families may experience should be acknowledged. While clinicians should ensure their TS patients are given regular psychiatric assessments until adulthood. Researchers have often been discouraged from including participants with co-morbid conditions in their studies as reviewers criticised studies for not separating findings from participants with TS alone, or TS with other conditions. Given the study’s claim that 86% of individuals with TS will experience a further psychiatric disorder during their lifetime studies which include participants with co-morbidities are needed.
Hirschtritt, M. E., Lee, P. C., Pauls, D. L., & et al. (2015). LIfetime prevalence, age of risk, and genetic relationships of comorbid psychiatric disorders in tourette syndrome. JAMA Psychiatry. doi: 10.1001/jamapsychiatry.2014.2650
Dr Charlotte Beer, Assistant Professor in Behavioural Sciences, CANDAL member