There is evidence that adult substance abusers tend to have high rates of psychiatric symptomatology and diagnosable psychiatric disorders and that those with more severe psychiatric problems show lower levels of improvement. This paper examines whether these same two findings also hold for adolescent substance abusers. The outcome of treatment, in a day treatment center in a private vocational high school setting, for 130 court-referred substance-abusing delinquent boys aged 14 to 18 years was studied in relation to their psychic symptomatology at admission, as measured by the Brief Symptom Inventory and the Emotional Reaction Inventory. The unexpected finding, although not conclusive, shows that there is a slight tendency among these young clients for those who report more psychiatric symptoms to improve more, rather than less, with treatment. For example, a greater score on the borderline psychotic subscale of the Emotional Reaction Scale predicted to more improvement as measured by reduction in drug use. A response set explanation was postulated for this finding: those clients who were more self-evaluative and more open and self-revealing about their disturbing inner thoughts and feelings might have been more trusting, more ready, and better motivated for counseling. The following are some possible explanations for the fact that the findings are different from those of some studies reported for adult substance abusers: adolescent drug abusers have, or are aware of having, or report, less psychiatric symptomatology, than adult abusers or addicts; our study sample included only court-referred delinquents; and there are differences in research methodology, specifically in the types of instruments and measures used.(ABSTRACT TRUNCATED AT 250 WORDS)