@article {ChengE583, author = {Jur-Shan Cheng and Jing-Hong Hu and Ming-Yu Chang and Ming-Shyan Lin and Hsin-Ping Ku and Rong-Nan Chien and Ming-Ling Chang}, title = {Hepatitis C{\textendash}associated late-onset schizophrenia: a nationwide, population-based cohort study}, volume = {46}, number = {6}, pages = {E583--E591}, year = {2021}, doi = {10.1503/jpn.200154}, publisher = {Journal of Psychiatry and Neuroscience}, abstract = {Background: Whether infection with the hepatitis C virus (HCV) causes schizophrenia {\textemdash} and whether the associated risk reverses after anti-HCV therapy {\textemdash} is unknown; we aimed to investigate these topics.Methods: We conducted a nationwide, population-based cohort study using the Taiwan National Health Insurance Research Database (TNHIRD). A diagnosis of schizophrenia was based on criteria from the International Classification of Diseases, 9th revision (295.xx).Results: From 2003 to 2012, from a total population of 19 298 735, we enrolled 3 propensity-score-matched cohorts (1:2:2): HCV-treated (8931 HCV-infected patients who had received interferon-based therapy for >= 6 months); HCV-untreated (17 862); and HCV-uninfected (17 862) from the TNHIRD. Of the total sample (44 655), 82.81\% (36 980) were 40 years of age or older. Of the 3 cohorts, the HCV-untreated group had the highest 9-year cumulative incidence of schizophrenia (0.870\%, 95\% confidence interval [CI] 0.556\%{\textendash}1.311\%; p \< 0.001); the HCV-treated (0.251\%, 95\% CI 0.091\%{\textendash}0.599\%) and HCV-uninfected (0.118\%, 95\% CI 0.062\%{\textendash}0.213\%) cohorts showed similar cumulative incidence of schizophrenia (p = 0.33). Multivariate Cox analyses showed that HCV positivity (hazard ratio [HR] 3.469, 95\% CI 2.168{\textendash}5.551) was independently associated with the development of schizophrenia. The HCV-untreated cohort also had the highest cumulative incidence of overall mortality (20.799\%, 95\% CI 18.739\%{\textendash}22.936\%; p \< 0.001); the HCV-treated (12.518\%, 95\% CI 8.707\%{\textendash}17.052\%) and HCV uninfected (6.707\%, 95\% CI 5.533\%{\textendash}8.026\%) cohorts showed similar cumulative incidence of mortality (p = 0.12).Limitations: We were unable to determine the precise mechanism of the increased risk of schizophrenia in patients with HCV infection.Conclusion: In a population-based cohort (most aged >= 40 years), HCV positivity was a potential risk factor for the development of schizophrenia; the HCV-associated risk of schizophrenia might be reversed by interferon-based antiviral therapy.}, issn = {1180-4882}, URL = {https://www.jpn.ca/content/46/6/E583}, eprint = {https://www.jpn.ca/content/46/6/E583.full.pdf}, journal = {Journal of Psychiatry and Neuroscience} }