Patients with HCV infection often suffer from chronic fatigue, depression and reduced cognition, even before evolving severe liver fibrosis, liver cirrhosis and hepatic encephalopathy.

It is currently unclear to what extent the symptoms er due to a direct pathological effects of the virus itself, or due to pre-existing psychiatric disease. There is a complex relationship between prior or existing drug abuse, psychiatric disease and HCV infection, that makes it difficult to establish cause-effect relationships.

A biological mechanism has been suggested to contribute to development of cerebral dysfunction in the patients. According to the prevailing Trojan Horses hypothesis circulating lymphocytes cross the blood brain barrier carrying HCV to the central nervous system and virus is subsequently replicated in the macrophages and the microglia in brain as a separate compartment. As part of the immunological response to viral replication, neurodegenerative processes takes place with a harmful effect on the neural circuit and cerebral function. Identification of HCV RNA negative strand, a replication product, in brain tissue from HCV patients, as part of autopsy studies, supports the hypothesis. Moreover, HCV patients have also been observed with abnormal metabolic concentrations in the frontal white substance and the basal ganglia by MRI spectroscopy compared to control groups.

The overall study objective is to assess cerebral function with particular emphasis on cognitive functions in HCV patients (genotypes 1,2 and 3) receiving peginterferon and ribavirin therapy by use of a neuropsychiatric test battery. Furthermore, the patients will in the same pre- and post-treatment study design be examined by MRI, including magnetization transfer, diffusion tensor and contrast perfusion, in order to perform measurements of cerebral volumetric and microstructure. Finally, HCV analysis, including viral sequences and cytokine profiles, in serum and cerebrospinal fluid will be carried out in the study population.