All subjects in the study were invited to participate in interviews at two-year intervals. Detailed information on participation is provided in [23] Bucholz et al., 2017. Information on all available interviews for each subject was combined in the present analysis with age of onset assigned according to the earliest description of psychopathology and a judgment of severity based on the time when the most symptoms were described. Every subject with at least one complete interview was included in the analysis.
