Screening data, including results of the Problem Oriented Screening Instrument for Teenagers (POSIT) developed by the NIDA, on arrested youths processed in May 1993 at the Hillsborough County, Florida Juvenile Assessment Center are analyzed. High rates of potential psychosocial functioning problems were obtained. Relationships were found between the youths' POSIT results, their dependency and delinquency referral histories, self-reported alcohol and marijuana/hashish use and their claimed involvement in mental health or substance use treatment-for which problems they were seriously underserved. The service delivery and policy implications of our findings are drawn.