Gilles de la Tourette Syndrome, Depression, Depressive Illness, and Correlates in a Child and Adolescent Population

Objective: Gilles de la Tourette syndrome (GTS) and depression are both common disorders. It has been suggested that depression occurs in 13%-76% GTS patients. Despite this, there are few studies into the specific relationships and correlates between the two disorders. There is only some consensus as to the precise relationship between the two disorders.Materials and Methods: We undertook the study to investigate the relationship between depressive symptomatology and the core clinical features of GTS in a well-characterized clinical population of youth with this disorder. Our aim was to verify the association between depression and comorbid obsessive-compulsive disorder and explore further other potential associations highlighted in some, but not all, of the studies focused on this topic.Results: Our results demonstrated that (1) the GTS patients were significantly older than the controls, (2) the GTS patients were significantly more depressed than controls, (3) depression was associated with tic severity, (4) the Diagnostic Confidence Index scores were higher in GTS patients without depression, (5) anxiety, attention-deficit/hyperactivity disorder (ADHD), conduct disorder (CD), and behavioral problems were significantly associated with depression, and (6) finally, patients with GTS and depression have a positive family history of depression. However, obsessionality (CY-BOCS) did not differentiate between depressed and not depressed GTS patients.Conclusions: Depression is common in patients with GTS and occurs significantly more in GTS than in controls. Depression is significantly associated with GTS factors such as tic severity, comorbidity with ADHD, and the presence of coexistent anxiety, CDs, and behavior problems. Depression is importantly significantly associated with a positive family history of depression. Intriguingly, depression in our sample was not related to obsessionality.