Aims: To examine among maintenance patients (methadone or buprenorphine) with and without hepatitis C virus (HCV) infection (i) the frequency of psychopathological symptoms at baseline and 1-year follow-up; (ii) the association between antiviral interferon (IFN) treatment and psychopathological symptoms; and (iii) to explore whether IFN therapy has an effect on 1-year outcome of maintenance treatment.
Design: Naturalistic prospective longitudinal cohort design.
Setting: A total of 223 substitution centres in Germany.
Participants: A nationally representative sample of 2414 maintenance patients, namely 800 without and 1614 with HCV infection, of whom 122 received IFN therapy.
Measures: HCV infection (HCV+/HCV-), IFN (IFN+/IFN-) treatment status and clinical measures. Diagnostic status and severity (rated by clinician), psychopathology (BSI--Brief Symptom Inventory) and quality of life (EQ-5D--EuroQol Group questionnaire).
Findings: HCV+ patients revealed indications for a moderately increased psychopathological burden and poorer quality of life at baseline and follow-up compared to HCV- patients. HCV+ patients showed a marked deterioration over time only in the BSI subscale somatization (P = 0.002), and the frequency of sleep disorders almost doubled over time (12.8% at baseline; 24.1% at follow-up; P < 0.01). IFN treatment, received by 10% of HCV+ patients, did not impair efficacy or tolerability of maintenance therapy and was associated overall with neither increased psychopathological burden nor reduced quality of life.
Conclusions: Findings suggest no increased risk among HCV+ patients on maintenance therapy for depressive or other psychopathological syndromes. In our patient sample, IFN treatment was not associated with increased psychopathological burden, reduced quality of life or poorer tolerability and efficacy of maintenance treatment.