Comorbidity is a common problem in dealing with any mental health problem. Bipolar disorder and Tourette's syndrome are not commonly comorbid conditions but existing cases are fascinating.
Is there a link between bipolar disorder and tourettes? Tourette's syndrome and bipolar disorder are two very different disorders. Tourette's syndrome is a neurodevelopmental disorder characterised by the presence of multiple motor and one or more vocal and/or phonic tics. Symptoms must occur for over a year in order to receive a diagnosis.Tourette's syndrome usually begins around age six or seven and is a lifetime disorder. There is thought to be a prevalence rate of between 0.46% and 1.85% for those aged between five and 18. Bipolar disorder is an affective disorder characterised by episodes of mania or hypomania and depression. It can be recurrent or chronic.
Comorbidity of all conditions is extremely common. Studies suggest that between 25% and 50% of people with one disorder have at least one comorbid condition. Comorbidity can be problematic as it hinders diagnosis, alters the course of a disorder and complicates treatment. Although all disorders present problems of comorbidity different disorders are more likely to be comorbid with certain disorders than others.
Comorbidity of Bipolar Disorder
Bipolar disorder is most commonly comorbid with substance use disorders and anxiety disorders. The epidemiologic catchment area (ECA) study found that 46% of the bipolar disorder patients included in the study reported alcohol abuse or dependence and 41% reported drug abuse or dependence. The national comorbidity survey (NCS) study found that 71% of bipolar disorder patients included the study reported at least one lifetime substance use disorder. 61.1% reported being alcohol depedent, 64.2% reported being alcohol abusers, 40.7% reported being drug dependent and 46.1% reported being drug abusers. With regards to anxiety disorders, an overwhelming 92% of bipolar disorder patients were found to have a comorbid anxiety disorder in the NCS. The ECA reported that 21% of patients had comorbid panic disorder and 21% had comorbid OCD.
Comorbidity of Tourette's Syndrome
Tourette's syndrome is most commonly comorbid with ADHD and obsessive-compulsive-disorder (OCD). In fact, a type of Tourette's named Tourette's Syndrome Plus has been suggested to describe Tourette's patients who also present with ADHD, OCD or self-harming behavior.The comorbidity rate between Tourette's and ADHD is between 60% and 80% and the disorders share an overlapping clinical spectrum. This knowledge has led to a suggestion that the disorders share a neurobiological basis. The reported comorbidity rate between Tourette's and OCD varies between 11% and 80%. The disorders share many similarities; they are both childhood onset lifelong conditions which are partly exacerbated by stress. It has been suggested that certain obsessive compulsive symptoms or behaviours represent another expression of Tourette's syndrome.
The Relationship Between Bipolar Disorder and Tourette's Syndrome
Affective disorders are also commonly comorbid with Tourette's syndrome. However, unipolar depression is far more commonly seen in cases of Tourette's syndrome than bipolar disorder. Some cases of comorbid Tourette's syndrome and bipolar disorder have been seen. Although the number of cases hinting at a link between bipolar disorder and tourettes are small, they are notable. It has been found that Tourette's syndrome plus patients (those with comorbid ADHD and/or OCD) with comorbid bipolar disorder present with peculiar features and are particularly difficult.
However, there is not thought to be a link between Tourette's syndrome and bipolar disorder per se but a link between bipolar disorder and another comorbid condition. OCD is the most likely condition to link with bipolar disorder to create these strange cases of Tourette's syndrome. Depression is the most common consequence of OCD and treatment of OCD with selective serotonin reuptake inhibitors (SSRI's) can precipitate mania. It will be interesting to follow research developments regarding the relationships and possible links among mental disorder as they are made available.
Hirschfeld, R. & Vornik, L.A. (2005) Bipolar disorder - costs and comorbidity. The American Journal of Managed Care. 11: S85-S90.
Cavanna, A.E., Servo, S., Monaco, F. & Robertson, M.M. (2009) The behavioural spectrum of Gilles de la Tourette Syndrome. Journal of Neuropsychiatry and Clinical Neuroscience, 21:1, 13-22.