We linked nationwide Swedish registers via the unique 10-digit identification number assigned at birth or immigration to all Swedish residents. The identification number was replaced by a serial number to ensure anonymity. The following sources were used to create our dataset: the Total Population Register, containing information about year of birth, sex, and yearly information on family and marital status from 1990; the Swedish Census, containing household information in 1960, 1965, 1970, 1975, 1980, 1985, and 1990; the Multi Generation Register, linking individuals born after 1932 to their parents; the Twin Register, including information of known zygosity with 95 % validity; the Hospital Discharge Register, containing hospitalizations for all Swedish inhabitants from 1964–2010; the Prescribed Drug Register, containing all prescriptions in Sweden picked up by patients from July 2005 to December 2010; the Outpatient Care Register, containing information from outpatient clinics from 2001 to 2010 (excluding Primary Health Care); the Primary Health Care Register, containing outpatient diagnoses from 2001–2007 for around 1 million patients from Stockholm and southern Sweden; the Crime Register that included national complete data on all convictions
