Suicide in Tourette's and Chronic Tic Disorders

Background: Persons with neuropsychiatric disorders are at increased risk of suicide, but there is little data concerning Tourette's and chronic tic disorders (TD/CTD). We aimed to quantify the risk of suicidal behavior in a large nationwide cohort of patients with TD/CTD, establish the contribution of psychiatric comorbidity to this risk, and identify predictors of suicide.

Methods: Using a validated algorithm, we identified 7736 TD/CTD cases in the Swedish National Patient Register during a 44-year period (1969-2013). Using a matched case-cohort design, patients were compared with general population control subjects (1:10 ratio). Risk of suicidal behavior was estimated using conditional logistic regressions. Predictors of suicidal behavior in the TD/CTD cohort were studied using Cox regression models.

Results: In unadjusted models, TD/CTD patients, compared with control subjects, had an increased risk of both dying by suicide (odds ratio: 4.39; 95% confidence interval [CI]: 2.89-6.67) and attempting suicide (odds ratio: 3.86; 95% CI: 3.50-4.26). After adjusting for psychiatric comorbidities, the risk was reduced but remained substantial. Persistence of tics beyond young adulthood and a previous suicide attempt were the strongest predictors of death by suicide in TD/CTD patients (hazard ratio: 11.39; 95% CI: 3.71-35.02, and hazard ratio: 5.65; 95% CI: 2.21-14.42, respectively).

Conclusions: TD/CTD are associated with substantial risk of suicide. Suicidal behavior should be monitored in these patients, particularly in those with persistent tics, history of suicide attempts, and psychiatric comorbidities. Preventive and intervention strategies aimed to reduce the suicidal risk in this group are warranted.