The first study group consists of participants from the Health 2000 cohort study, which is a nationwide population-based health interview and examination survey carried out in Finland in 2000–2001. The study is described in detail elsewhere (Aromaa and Koskinen, 2004). The survey has been accepted by the ethics committees of the National Public Health Institute and the Helsinki and Uusimaa Hospital District, and all participants provided a written informed consent. The cohort includes 8028 individuals with age 30 or over. A total of 5955 participants donated blood samples and took part in a health status examination. Alcohol dependence and alcohol abuse as well as mood and anxiety disorders were assessed by using a diagnostic mental health interview, Munich-Composite International Diagnostic Interview (M-CIDI), yielding the diagnosis based on DSM-IV criteria (Diagnostic and Statistical Manual of Mental Disorders, 4th edn, American Psychiatric Association 2000). The subpopulation analyzed in the current study included all cases with a diagnosis of alcohol dependence or alcohol abuse (n = 512) and their sex- and age-matched controls having no mental disorders (n = 511). There were 99
