Behavioral Techniques for Assessing Drug Tolerance and Sensitization

The term tolerance typically refers to the relatively common observation that during chronic drug treatment the effect(s) of some drugs may progressively reduce in magnitude. For example, there is now evidence suggesting that in a variety of animal models of anxiety, the anxiety-reducing actions of the widely prescribed benzodiazepine drugs show tolerance during long-term treatment (Vellucci and File, 1979 117 ; Treit, 1985 116 ; Stephens and Schneider, 1985 108 ). In contrast to tolerance, the term sensitization refers to the observation that during chronic treatment some drug effects actually increase in magnitude. For example, it is well established that sensitization develops to the motoric effects of psychostimulant drugs (Kilbey and Sannerud, 1985 69 ) and to the therapeutic effects of antidepressants