Depression is a common adverse event in patients with chronic hepatitis C treated with interferon. The aim of the study, based on the Department of Gastroenterology at the University of Michigan (United States), was to determine the initial and emerging prognostic factors for the development of depression in patients with chronic viral hepatitis C receiving treatment with peginterferon or ribavirin.

The study "Long-term antiviral therapy for hepatitis C for cirrhosis" (Long-term antiviral therapy for hepatitis C for cirrhosis) involved 201 patients with severe fibrosis. All study participants received peginterferon alfa-2a (180 g / week) and ribavirin (1.0-1.2 g / day) for 24 weeks, and 74 patients with undetectable virus RNA hepatitis C at week 20 continued to receive the same treatment for 48 weeks. The patients' mood was assessed using a Beck Depression Inventory II rating scale and the Composite International Diagnostic Interview. Plasma cortisol and serotonin levels in whole blood were determined in 101 patients at weeks 0, 4, 24, 48 and 72.

The incidence of interferon-induced depression was found to be 23% and 42% at 24 and 48 weeks, respectively, and in 74 patients who responded to treatment, the incidence of depression at week 24 was only 9%. Although 22% of patients initially (before treatment) showed symptoms of depression, the absence of a virological response at week 20 was the only independent prognostic factor (predictor) for the development of interferon-induced depression at week 24 (p = 0.0009). It should be noted that at week 72, the mean score on the Beck II depression scale returned to the level recorded before treatment, which indicates the reversibility of the interferon-induced depression.

Plasma cortisol levels did not change during treatment and were not correlated with depression, indicating that the hypothalamic-pituitary-adrenal system is not responsible for the development of mood changes. Plasma and platelet serotonin levels decreased significantly during treatment, but were not correlated with the onset of interferon-induced depression before week 24 (p = 0.35) or before week 48 (p = 0.51).

Thus, the occurrence of depression during treatment with peginterferon and ribavirin is associated with the absence or an unexpressed virological response. A significant decrease in the level of serotonin in whole blood over time indicates the need for further studies to identify the pathological serotonergic mechanisms and determine the mediators of interferon-induced depression.