During the past year, we have continued to analyze the data from this unique prospective cohort study that covers a total observation period of 30 years for this cohort of young adults who have been followed since the age of 18. In collaboration with our colleagues in Zurich, we have completed a recently published analysis describing the frequency of occurrence of mental disorders across adulthood, taking into account information from the latest wave of follow-up in 2008. This is the only study that has described these patterns among a cohort starting in young adulthood. Analyses approximate the lifetime risk of disorders through age 50. Results indicate that mental disorders occur relatively commonly across this age range; lifetime risks range from 1.21% for Bipolar I Disorder to 32.54% for Major Depressive Disorder. These findings, that it is relatively common for people to experience at least one episode of mental disorder across the course of adulthood, have led us to ask what proportion of adults in the general population experience repeated or chronic episodes of mental disorder across adulthood. We have begun a project that will address this question in the Zurich Cohort Study. The Zurich Cohort Study's prospective, longitudinal design makes it one of only a few data sources in which this question can be investigated without relying on long periods of retrospective recall. We will investigate the persistence of specific categories of mental disorder, including mood, anxiety, phobias, and substance use disorders, and of mental disorder in general. We will also investigate sex differences in the persistence of mental disorders across adulthood. Public Health Impact: These studies provide valuable insight into the nature of mental disorders and their burden among adults across time. The Zurich Cohort Study is an extremely valuable data source, as it is the longest community-based longitudinal study in which participants were enrolled at the beginning of adulthood. Data on the frequency and persistence of mental disorders are important for planning interventions and service delivery as well as for research on etiology. Our investigation of the persistence of mental disorders may provide a valuable counterpoint to the high lifetime prevalence rates that are often reported in community surveys of mental disorder. Future Plans: During the next year, in addition to completing the project described above, we plan to analyze the 30 year follow-up data on the following topics: 1) the reliability of participant-reported prevalence and age of onset of mental disorders in community-based studies; 2) the comorbidity of physical health conditions and mental disorders across adulthood; 3) patterns of sleep across adulthood and the relationship between sleep and mental disorders; and 4) the spectrum of mania, hypomania, and depression in the general population, including order of onset and patterns across age.
