Tic-Related Functional Impairment Drives the Relationship Between Tics and Depression in Youth With Tourette Syndrome.

Although many youth with Tourette syndrome (TS) have at least 1 comorbid psychiatric condition (eg, obsessive-compulsive disorder), the extent to which TS is associated with depression remains unclear. This cross-sectional study examined relationships among tic severity, tic-related functional impairment, and depressive symptoms in 277 youth with TS. Tic-related impairment, but not tic severity, was associated with both self- and parent-reported depressive symptoms. An age × sex interaction emerged, such that among younger participants, females reported higher depressive symptoms than males; however, this effect was observed only for self-report, not parent report. Additionally, both depressive symptoms and tic severity were associated with quality of life, though depressive symptoms accounted for substantially more variance. Overall, findings suggest that associations between tics and depression are modest and largely driven by impairment rather than tic severity per se. Depressive symptoms, however, significantly impact quality of life in youth with TS and warrant clinical attention.