Discontinuation syndrome in dysthymic patients treated with selective serotonin reuptake inhibitors - A clinical investigation

Objective: Many authors have reported discontinuation symptoms associated with selective serotonin reuptake inhibitors (SSRIs). The aim of this study was to investigate the incidence and characteristics of the discontinuation syndrome in patients who stopped treatment with the SSRIs paroxetine and fluoxetine under the usual conditions of clinical practice, and to identify clinical predictors of the syndrome. Methods: Ninety-seven outpatients who received an initial diagnosis of dysthymic disorder, who responded to ≥8 weeks treatment with paroxetine (n = 52) or fluoxetine (n = 45), and who discontinued the SSRI according to their psychiatrist's instructions were included. They were assessed at the time of discontinuation using a semi-structured interview for clinical and treatment characteristics, the Hamilton Depression Rating Scale (HAM-D) and the Montgomery-Åsberg Depression Rating Scale (MADRS). Patients were then assessed 4 weeks later using a checklist for discontinuation symptoms, a semi-structured interview for discontinuation symptom characteristics, and the HAM-D and the MADRS. Results: A discontinuation syndrome was found in 26 patients (26.8% of our sample); of this group, 22 patients (84.6%) had received paroxetine, and 4 patients (15.4%) had received fluoxetine. The mean time at onset of symptoms was 2 days after drug discontinuation and the mean duration was 5 days. The statistical comparison between the groups with and without a discontinuation syndrome found two significant differences - a discontinuation syndrome was more common in patients treated with paroxetine and in patients with an earlier onset of dysthymic disorder. Multiple regression analysis confirmed that these two factors were related to the duration of discontinuation symptoms, while the number of symptoms was associated with three factors, including use of paroxetine, age at onset of dysthmia and female gender. Conclusions: A discontinuation syndrome is common after treatment with SSRIs is stopped in patients with dysthymia, and it appears to be more common in patients receiving paroxetine than in those receiving fluoxetine. The syndrome is related both to drug and clinical characteristics. The features of the syndrome in patients with different Axis 1 diagnoses should be compared in further investigations.