Since late 1988, the Substance Use Disorders Work Group has considered alternative concepts and definitions of substance abuse and dependence and their significance for possible changes (in the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders) in existing criteria for abuse and dependence. The three other matters to which the group has devoted itself include the development of guidelines for distinguishing behaviors that typically accompany the abuse of specific substances from psychiatric disorders with similar behavioral consequences, examination of the predictive validity of possible alcoholic subtypes on the basis of family history, and the relationship of the organic brain syndromes to intoxication and withdrawal.