Obstetric medication versus residential area as perinatal risk factors for subsequent adult drug addiction in offspring.

In an attempt to explain pronounced uneven distributions of births of subsequent amphetamine and opiate addicts at seven hospitals in Stockholm, two possible mechanisms for adult drug addiction were weighed against each other: (1) risk factors associated with the obstetric care at the hospitals of birth of the addicts and (2) risk factors associated with the phenomenon of 'contagious' transmission of drug addiction in certain residential areas during adolescence. The subjects comprised 200 amphetamine addicts and 200 opiate addicts born between 1945 and 1966. By loglinear analysis the relative risk for future addiction was determined for eight residential areas as well as for the seven hospitals and four periods of birth. For the opiate addicts only one weak association was found for the residential area, which could not explain fully a clustering of births at any particular hospital. For the amphetamine addicts, hospital of birth was found to be an important risk factor even after controlling for residential area. Hence, the variable residential area has not been able to explain the uneven distribution of births of drug abusers among the studied hospitals.