Preclinical research on cocaine self-administration: environmental determinants and their interaction with pharmacological treatment

It has been asserted that any comprehensive understanding of cocaine abuse and its treatment will require attention to both behavioral and pharmacolog ical variables. Although the preclinical literature evaluating the effects of pharmacological variables on cocaine self-administration has been extens ively reviewed, no comprehensive review of the effects of environmental var iables on cocaine self-administration has been published. The present revie w summarizes and critiques the preclinical findings on environmental determ inants of cocaine self-administration. The influence of environmental varia bles on the effects of pharmacological interventions on cocaine self-admini stration are also described. Several environmental variables have been show n to affect cocaine self-administration, including unit dose, schedule of c ocaine delivery, schedules of nondrug stimuli, behavioral history, conditio ned stimuli, food deprivation, exposure to stress, and oaring environment. Among these variables, unit dose, schedule of cocaine delivery, availabilit y of alternative nondrug reinforcers, food deprivation, and rearing environ ment have also been shown to alter pharmacological treatment effects on coc aine self-administration. Thus, drug effects on cocaine self-administration are malleable and dependent upon the environmental context within which th ey occur. Suggestions for future research on the effects of these and other environmental variables on cocaine self-administration and its pharmacolog ical treatment are presented. (C) 1999 Elsevier Science Ltd. All rights res erved.