The study found that in a 1-year followup the youths who received intensive case-management services did not have significantly lower rates of drug use and related effects nor lower self-reported delinquency than youths who received only the standard features of the diversion program. Youths with higher psychopathy scores reported significantly more delinquency during the followup period than youth with lower scores on these measures, regardless of whether they received intensive case management or standard diversion components. These findings confirm that delinquent youths experience multiple problems that underlie their substance abuse and delinquent behaviors. Consequently, the development of interventions that effectively address these multiple needs and problems remains a challenge for policymakers, practitioners, and researchers. Following completion of a baseline interview with each youth, youths and their families who agreed to participate in the study were randomly assigned to 1 of 2 groups: the control group (n=84), which received the standard features of the diversion program, or the experimental group (n=81), which received additional intensive case management for 16 weeks. Delinquency was measured with the self-reported delinquency questions developed by Elliott, Ageton, Huizinga, Knowles, and Canter (1983). Psychosocial functioning and drug use and its consequences were assessed with the Comprehensive Adolescent Severity Inventory, a semistructured clinical assessment and outcome interview. 7 tables, 58 references, and appended supplementary data