Antidepressant-related jitteriness syndrome in anxiety and depressive disorders: Incidence and risk factors

Introduction Jitteriness syndrome (JS) is a poorly understood but important adverse effect of antidepressant drugs. This study examined the incidence and pattern of antidepressant-related JS and its predictors. Methods 209 patients diagnosed with any anxiety or depressive disorder and started on mirtazapine, sertraline, desvenlafaxine, escitalopram or fluoxetine were assessed at baseline, after 2 weeks, and after 6 weeks with psychopathology rating scales and for predefined categories of JS. Results The incidence of JS during the 6-week study was 27.7%, but only 6.7% in first 2 weeks. JS rates were similar in anxiety and depressive disorders. Mirtazapine was associated with the lowest rate of 14.3%, and other antidepressants with rates of 23–34%. High dose antidepressant treatment was significantly associated with JS (OR, 2.68; 95% CI, 1.37–5.25). No other variable predicted JS. JS was associated with significantly higher objective ratings of psychopathology. Discussion We conclude that up to a quarter of patients may suffer JS during the first 6 weeks of antidepressant initiation; higher antidepressant dose is a risk factor.