The use of a structured diagnostic interview (The Schedule for Affective Disorders and Schizophrenia) with 58 consecutively admitted general adult psychiatric patients revealed that 62.1% of them abused alcohol and 58.6% had a substance use disorder. The drug abusers did not differ significantly from the nonabusers on mean psychoticism (Brief Psychiatric Rating Scale) scores. However, they received higher doses of antipsychotic agents (mean daily dose 1022 mg CPZ EQ (SD = 614) vs 609 mg CPZ EQ (SD = 481); z = 2.58, p < .01) to achieve stabilization. The clinical implications of this finding are discussed.