Individuals with substance use disorders typically differ from controls on several dimensions of personality, including behavioral disinhibition (impulsivity), negative emotionality (pessimism), and positive emotionality (agreeableness). However, the degree of specificity to which the traits may be differentially linked to particular classes of substances is unclear. The sample comprised 325 subjects from the Yale Family Study investigating the relation between substance use disorders and anxiety disorders and their transmission in families. Subjects were recruited from both outpatient treatment facilities and the general population. They were interviewed using a modified version of the Schedule for Affective Disorders and Schizophrenia (SADS), which assesses sufficient information to produce psychiatric diagnoses. The Multidimensional Personality Questionnaire (MPQ) was used to measure three high-order personality dimensions--positive emotionality, negative emotionality, and constraint. Findings show that individuals with substance abuse/dependence, compared to those without, scored lower on constraint even after adjusting for sociodemographic factors, comorbid psychiatric disorder, and current/remitted substance-use disorder. Individuals with substance abuse/dependence scored marginally higher on negative emotionality, but this difference was statistically significant only when comorbid psychopathology was not controlled. Findings show that individuals who differ with respect to drug of choice vary in terms of constraint. Scores on constraint generally decreased with the social deviance of the drug of choice, after controlling for sociodemographic indicators and comorbid psychopathology. This underscores a potentially important link between disinhibition and drug selection. 3 tables, 90 references