Mental illness and substance abuse, which often co-occur among juvenile offenders, can contribute substantially to delinquent behavior. It is estimated that perhaps between 77 percent and 93 percent of juvenile offenders suffer from mental illness, far higher than the 10-20 percent estimated prevalence rate among the non-delinquent juvenile population. Lack of appropriate treatment in adolescence may lead to further delinquency, adult criminality, and adult mental illness. Psychosocial and environmental risk factors also contribute to juvenile offending. Frequently it is difficult to determine which mental illness or risk factor is the greater source of problems because juvenile offenders often have multiple mental illnesses and/or are exposed to multiple risk factors. The most common diagnoses for juvenile offenders are alcohol dependence, major depression/dysthymia, attention deficit hyperactivity disorder, bipolar disorder (manic depression), generalized anxiety disorder, and post-traumatic stress disorder. References