Indications, efficacy and side-effects of the selective serotonin reuptake inhibitors (SSRI) have now been investigated in numerous studies of varying quality. In the case of some disorders, SSRI have been shown to produce a very positive response-for example compulsive disorders and seasonal winter depression, so-called. In view of their effectiveness, SSRI are now considered first-line drugs for these indications. With respect to other disorders, SSRI are recommended because of their favorable side-effect profile. In further indications the efficacy reported in individual studies need further corroboration. Differences between individual SSRI, which mainly concern kinetics, are described.