AbstractVarious types of drugs that have been proposed as treatments might alter cognitive processes. Programmatic research in this area is built upon knowledge about the psychobiological bases of learning, memory, and related cognitive processes. These efforts generally begin with promising research findings obtained from psychopharmacological studies of cognitive processes in lower animals. These findings are then integrated with what is known about the neuropathology of syndrome‐related types of cognitive failures in humans along with findings relating to the determinants of information processing in both impaired patients and unimpaired subjects. Experiments are then designed to test the cognitive response to some psychoactive drug treatment. Promising leads and preliminary claims and findings are frequently not supported by continued clinically focused research. A major reason is that studies do not adequately consider the differentiated nature of cognitive processes. This paper stresses a single theme—namely, cognitive processes are complex, differentiated, and determined by different psychobiological mechanisms and, therefore, are susceptible to change in relatively specific ways. A theoretical framework for the analysis of cognitive changes is proposed. This framework is used illustratively to profile how different types of cognitive responses may result from different types of drug treatm