Objective Affective symptoms are frequently reported by patients with tic disorders and Tourette syndrome in particular. Depression in the context of Tourette syndrome is likely to be aetiologically multifactorial and phenotypically heterogeneous. Despite the known impact of depression on health-related quality of life of patients with neuropsychiatric disorders, little research has been conducted on the clinical aspects of affective symptoms associated with Tourette syndrome. We set out to assess the clinical phenomenology and severity of depressive symptoms in adult patients with Tourette syndrome compared to adult patients with major depression and healthy controls.

Method The Beck Depression Inventory (BDI) was used to collect self-report ratings of depressive symptoms from 65 patients with Tourette syndrome (BDI-II), 293 healthy controls (BDI-IA) and 696 patients with a lifetime diagnosis of recurrent major depressive disorder (BDI-IA). All clinical diagnoses were validated by DSM criteria and direct comparisons were possible for 14 out of the 21 BDI items. Patients with Tourette syndrome were recruited at a specialist tertiary referral clinic, whereas patients with a primary diagnosis of depression and healthy controls were extracted from a large multicentre research database developed for the investigation of genetic and non-genetic determinants of affective disorders.

Results Patients with Tourette syndrome reported significantly higher total BDI scores than healthy controls

Conclusion Depression is confirmed as a major clinical issue in patients with Tourette syndrome. Self-report ratings of overall depression severity in this patient population are similar to those reported by patients with a primary diagnosis of recurrent major depressive disorder. There are however specific differences in the clinical phenomenology of depressive symptoms, as irritability is a more prominent feature in patients with Tourette syndrome. Routine screening for affective symptoms with particular focus on the assessment of irritability symptoms is warranted in order to implement effective treatment strategies as appropriate. Future research is needed to better understand the relationship between tic symptoms, irritability and depression in Tourette syndrome.