Self-report measures of problemsolving ability and locus of control were administered at all testing periods. Two multivariate analyses of covariance and six univariate analyses of covariance were used to assess group differences in posttest and followup problemsolving and locus of control measures, as well as followup adjustment scores. Contrary to the underlying theory of treatment regarding the effects of incarceration, prisoners exhibited an internal locus of control and adequate problemsolving skills. Thus, prisoners already possessed characteristics that treatment was implemented to facilitate. Various explanations for the study findings are offered, and implications of the findings for clinical work and research are discussed. 47 references