This study investigated MAPI scale patterns among adolescent psychiatric inpatients along a dimension of substance abuse deviancy; no substance abuse; alcohol abuse only; alcohol and marijuana abuse only; other substance abuse plus alcohol and/or marijuana abuse. The findings showed the most notable distinction involved the issue of non-alcoholic substance abuse. Psychiatric inpatients who abuse alcohol were little different from patients with no substance abuse diagnosis. Conversely, those patients who abused the more culturally deviant non-alcoholic substances were markedly different than non-substance abusing or alcohol-only abusing patients in several respects; highly negativistic attitudes toward family, authority and conformity; personality styles marked by aggressiveness and labile negativism and low conscientiousness; behavioral trait of impulsivity; poor sense of academic confidence. Only these non-alcoholic substance abusing psychiatric patients may require a distinctively different treatment plan than the protocol for uncomplicated psychiatric disorder. (C) 1995 The Association for Professionals in Services for Adolescents