The possible role of serotonin transporter activity in major depressive disorder of patients with untreated chronic hepatitis C virus infection – investigation on platelets

Background: Interferon-α-induced depression in patients with chronic hepatitis C (CHC) is acknowledged to be related to alterations in serotonergic neurotransmission. No studies have reported on similar biological correlates in untreated CHC with clinically diagnosed major depression. The present study addressed this issue by examining whether untreated patients with CHC are different from healthy control subjects (HCS) with respect to serotonin (5HT) transporter activity and 5HT levels in platelets, and whether the possible abnormalities are specifically related to patients who exhibit symptoms of depression in subclinical and clinical range. Results: Single episode of major depression, mild or moderate, was diagnosed in 5 of the 65 patients. Additional 7 patients were classified as subsyndromal depression. In this group of 12 patients mean platelet 5HT uptake activity was significantly higher compared to non-depressed patients or HCSs (76.3 ± 18.3 vs. 62.2 ± 13.8 vs. 52.9 ± 10.0 pMol [14C]-5HT/109 × 5 min, respectively). Mean platelet 5HT level was also significantly higher in patients with clinical or subsyndromal depression (604 ± 217 vs. 459 ± 223 vs. 400 ± 111 ng/109 plts, respectively). Conclusion: Our findings suggest a possible specific role of high serotonin transporter activity in major depression associated with CHC. Permanent and pronounced high 5HT uptake activity in platelets of non-treated viremic patients could be an indicator for clinical/subclinical depression.