The iPSYCH2015 sample is a nation-wide population sample extracted from a baseline cohort consisting of all children born in Denmark between May 1, 1981, and December 31, 2008, who were alive and resided in Denmark on their one-year birthday, and who have a known mother25,26. Individuals diagnosed with one (or more) of six major psychiatric disorders (ADHD, autism, depression, bipolar disorder, schizophrenia, anorexia) were identified via the Danish Psychiatric Central Research Register27, which includes data on all individuals treated in Denmark at psychiatric hospitals (from 1969 onward) as well as at outpatient psychiatric clinics (from 1995 onward). A random sample from the same birth cohort were chosen as control group. The iPSYCH2015 cohort consists of the initial case-cohort sample iPSYCH201226 and the recent extension iPSYCH2015i25.
