During interviews drug-abusing offenders provided information on the backgrounds, childhood histories, biological relatives, current behaviors, and criminal and drug histories. Additionally, several psychological inventories were administered to evaluate the presence of depression, anxiety, psychopathy, and impulsivity. Results indicate that frequency of specific drug use and drug of choice were significantly associated with particular measures of psychopathology. Subjects with a high frequency of alcohol use reported higher levels of anxiety and impulsivity and had higher scores on measures of psychopathy and neuroticism than those who consumed smaller amounts of alcohol over time. Subjects who reported high levels of marijuana use were more suspicious, neurotic, and psychopathic and had a higher incidence of head injury. These subjects were also heavier drinkers than subjects who reported less marijuana use. The greater the frequency of cocaine use among subjects, the more property crimes they committed and the higher the scores related to psychopathy. Subjects who reported using heroin more frequently were less likely to have a history of psychiatric problems compared with those who used heroin less often. Total drug-use frequency was positively associated with a number of conditions, including irritability, indirect hostility, neuroticism, and psychopathy, and negatively related to socialization. 4 tables and 57 references