The estimated global prevalence of hepatitis C (HCV) infection is approximately 3% (170 million individuals). In Canada there are an estimated 240,000 people infected with HCV. The current study addresses the hypothesis that neurocognitive and neurochemical abnormalities may occur in individuals with HCV-infection who do not have liver cirrhosis or vasculitic neuropathy, and this may result from a direct effect of HCV on the Central Nervous System (CNS). The purpose of this study is to assess whether infection with the Hepatitis-C virus is associated with changes in thinking skills and brain chemistry, in patients who do not have liver cirrhosis. In addition, we are examining whether such changes in thinking skills and brain chemistry are reversed by antiviral treatment. We are also studying whether factors such as fatigue and depression have an effect on thinking skills in people with Hepatitis-C. In order to take into account the impact of having viral hepatitis, we will be comparing the results of the Hepatitis-C group to the results of a group of patients with Hepatitis-B, and to a group of individuals who do not have Hepatitis.