Predictors of antidepressant response to fluvoxamine obtained using the three-factor structures of the Montgomery and Asberg Depression Rating Scale for major depressive disorders in Japanese patients

Aims:  Fluvoxamine, a selective serotonin reuptake inhibitor, is widely used to treat major depression. However, the symptomatological predictors of the response to fluvoxamine have not been studied.
Methods:  This study included 100 Japanese patients who fulfilled the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria for the diagnosis of major depressive disorders and whose score on the Montgomery and Åsberg Depression Rating Scale (MADRS) was 21 or higher. Eighty-one patients were included. Patients with a pretreatment MADRS score of ≥31 were defined as 'severe' ( n  = 32) and the rest were defined as 'non-severe' ( n  = 49). The three-factor model of MADRS was used for analysis: the first factor was defined by three items, the second factor was defined by four items, and the third factor was defined by three items representing dysphoria, retardation, and vegetative symptoms, respectively. Fluvoxamine (100–200 mg/day) was administered twice daily for 6 weeks.
Results:  In the non-severe patients, the mean factor 3 score of the non-responders at pretreatment was significantly higher than that of the responders. However, a significant difference was observed in the mean factor 3 scores from 1 week onwards between the non-severe responders and non-responders. Furthermore, the fluvoxamine response rate in the severe patients was 75% and higher than that of the non-severe patients (65.3%).
Conclusions:  This study suggested that a low factor 3 score at pretreatment was a good predictor of the response to fluvoxamine in non-severe patients. The marked efficacy of fluvoxamine in the treatment of severe patients was also confirmed.