A comparison of the Aberrant Behavior Checklist and the GAF among adults with mental retardation and mental illness.

Psychiatric assessment among individuals with a diagnosis of both mental retardation and mental illness presents a clinical challenge. This retrospective study compared two rating scales--the Aberrant Behavior Checklist (ABC) and the Global Assessment of Functioning (GAF)--to determine the scales' utility in a partial hospital setting. Although ABC and GAF ratings were weakly correlated, the ABC revealed symptom patterns consistent with recognizable features of psychiatric syndromes and differential improvement in symptoms within and between diagnostic subgroups. The ABC provided a more useful measure of treatment response than the GAF in this patient population.