AIM: To assess systematically the spectrum and extent of depressive symptoms comparing patient groups receiving peginterferon or conventional interferon.METHODS: Ninety-eight patients with chronic hepatitis C and interferon-based therapy (+ribavirin) were consecutively enrolled in a longitudinal study. Patients were treated with conventional interferon alfa-2b (48/98patients; 5 MIU interferon alfa-2b thrice weekly) or peginterferon alfa-2b (50/98 patients; 80-150 μgpeginterferon alfa-2b) in combination with weight-adapted ribavirin (800-1 200 mg/d). Repeated psychometric testing was performed before, three times during and once after antiviral therapy: Depression was evaluated by the Hospital Anxiety and Depression Scale (HADS), anger/hostility by the Symptom Checklist-90 Items Revised (SCL-90-R).RESULTS: Therapy with pegylated interferon alfa-2bproduces comparable scores for depression (ANOVA:P = 0.875) as compared to conventional interferon.Maximums of depression scores were even higher and cases of clinically relevant depression were frequent during therapy with peginterferon. Scores for anger/hostility were comparable for both therapy subgroups.CONCLUSION: Our findings suggest that the extent and frequency of depressive symptoms in total are not reduced by peginterferon. Monitoring and management of neuropsychiatric toxicity especially depression have to be considered as much as in antiviral therapy with unmodified interferon.