[The integration of behavior as a variable in psychopharmacological research].
The place of animal behavioral research in C.N.S. pharmacology is discussed. The advantages of the most refined techniques presently available, namely operant conditioning, are described and illustrated with experiments concerning intra-individual, interindividual and interspecific homogeneity of drug action; duration of effect, dose-action relationship, tolerance, antagonism, synergism and potentiation. The possible contribution of an experimental analysis of drug action on behavior is not to the prediction of therapeutic properties generally founded in purely analogical and anthropomorphic reasoning but the understanding of functional mechanisms. As an example of such a mechanism, as approached by behavioral techniques, the transfer of behavioral effects from drugged to non-drugged states is discussed. When sufficiently refined methods are used, it becomes clear that the modifications of behavior observed under drugs cannot be explained by resorting to abstract psychological entities, such as anxiety, aggressiveness, activity, etc... A correct description emphasizes the differential effects of drugs on various behaviors, which a priori categorization would tend to consider as equivalent, and use as a simple index of some loosely defined pharmacological properties. Behavior under the control of aversive stimuli provides an example which illustrates the necessity to relate drug effects to experimentally defined variables rather than to invalidated constructs rejected by present day scientific psychology. The variability of drug effects according to the kind of behavior being considered, has led to the concept of drug-behavior interaction. Behavior should be treated in psychopharmacological research not only as a dependent variable, but, eventually, as an independent variable. Traditional approaches to behavioral pharmacology viewed behavioral changes as consequences of underlying physiological or biochemical changes. In some cases, it seems that part of the effects observed at behavioral levels are to be explained by the interference of specifically behavioral variables, or, in other terms, by the peculiar relations between the organism and its environment. Some typical problems raised by a behavioral analysis, in the field of tolerance and of experimentally induced addiction, are discussed.