The viability of birth order studies in substance abuse research.

Abstract

Examinations of the birth order literature for drug and alcohol abuse reveals equivocal and contradictory findings, many of which are methodologically suspect. The findings based on the 12-year follow-up of the Drug Abuse Reporting Program (DARP) suggest that there is very little support for birth order differences among drug abusers for age of initial drug use, severity of drug use, achievement of abstinence, or alcohol consumption. Finally, it is suggested that birth position is probably not a strong hypothesis for further research. Methodological difficulties, the likelihood of very small effect sizes (if any), and the uncertain theoretical status of birth position all detract from the viability of such investigations.