Antero- and retrograde amnesia are observed as side effects of most types of benzodiazepines. They have rarely been investigated with respect to physical and personality factors, or to prior experiences, present expectations, and emotional states of the subjects, all of which are well known to modify drug response. By reviewing research on benzodiazepine-induced changes of memory in preoperative, anxious, and depressed patients as well as in healthy subjects, it is demonstrated that differences in benzodiazepine-induced amnesic effects may depend on: 1. subject variables like predrug level of anxiety, depressive symptomatology, memory capacity, experiences with benzodiazepine-type drugs, and expectations of treatment outcome, and secondary factors like social environment and treatment setting 2. interactions between these subject variables and type of schedule (times of acquisition, treatment, and testing), type of learning material, and dose of drug. 3. the extent of benzodiazepine-induced changes in anxiety or depression, cortical and emotional arousal (alertness and activity) as well as physiological effects of benzodiazepines Special emphasis should be placed on the investigation of drug-induced changes of covariation between psychological measures which may provide valuable information for differential prediction and on mechanisms of drug action.