Abstract
Reviewed are 47 empirical studies. The paper contains sections on results from studies using specific psychometric instruments and measuring specific traits, personality differences in subgroups of heroin addicts, personality changes following treatment, and suggestions for future research. Measuring the presence or absence of a particular trait or characteristic is no longer sufficient. Rather, we need typologies within an interactional framework that systematically relates traits to other variables of interest (i.e., recidivism, treatment retention, and etiology).