The PRISM (formerly known as the SCID-A/D) is a semi-structured clinician-administered interview that measures the major Axis I DSM-IV diagnoses (current and past) of alcohol, drug, and psychiatric disorders. The PRISM was designed to provide clear guidelines for differentiating between the expected effects of intoxication and withdrawal, substance-induced disorders, and primary disorders. It is also useful for studying the effects of comorbidity on the longitudinal course of alcoholism or alcoholism treatment outcome. The PRISM can also be used to differentiate subjects in order to study treatment-matching strategies when psychopathology is one of the matching variables. The PRISM also covers two Axis II disorders, Borderline Personality Disorder and Antisocial Personality Disorder. This instrument was designed to maximize reliability and validity in heavy drinkers and users of drugs. Although primarily designed as a research instrument, the PRISM provides systematic coverage of alcohol- and drug-related experiences and symptoms that may be useful in identifying areas of focus for treatment. Additionally, the unusually high reliability of the depression diagnoses in individuals with heavy drinking may provide a better basis for treatment decisions than less consistent methods for assessing major depression and dysthymia.