Objective Tourette syndrome (TS) is a neuropsychiatric condition characterised by multiple motor and vocal tics, as well as a spectrum of behavioural problems. Previous research found that 76% of patients with TS experience depressive symptoms, with 13% fulfilling diagnostic criteria for depression. We set out to assess the severity of affective symptoms in patients with TS, in comparison to patients with primary affective disorders (recurrent major depressive disorder, rMDD; bipolar affective disorder types I/II, BPD-I/II), and healthy controls. Method Both patients with affective disorders and controls completed the Beck Depression Inventory (BDI)-IA, whilst patients with TS completed the BDI-II. Total BDI-II scores were transformed using an equipercentile equating method for converting raw total BDI-II to BDI-IA scores. Data from 14/21 items had corresponding anchor points between the two versions and were therefore suitable for analysis. Results This cross-sectional study included N=3,066 participants: TS (N=65), rMDD (N=696), BPD-I (N=1515), BPD-II (N=497), and controls (N=293). Depressive symptoms did not show any association with ethnicity or age. Patients with TS scored significantly higher than healthy controls (P= Conclusion Depression appears to be a prominent feature in TS and seems to have a different phenotype to that in rMDD. Female patients with TS present a particularly high risk to develop severe depressive symptoms. This has relevant clinical implications in terms of screening, management and prognosis of this patient population.