Conditioned opponent responses: effects of placebo challenge in alcoholic subjects

The present study continues a series of studies examining a number of variables that contribute to the demonstration of conditioned responses to alcohol in alcoholics. We pursued here the hypothesis that subjects receiving placebo in an environment previously associated with alcohol ingestion would exhibit conditioned responses as compared with subjects who had only received placebo in the environment. Further, we predicted that these conditioned responses would be opposite in direction to responses obtained during active drink sessions. Twelve subjects received active alcohol during session Days 1 through 4 and a placebo challenge on Day 5; the second group received placebo throughout sessions 1 through 5. On Day 1, heart rate and skin conductance were elevated following active alcohol ingestion as compared with placebo. On Day 5 following the placebo challenge, these physiological responses were significantly lower in the alcohol group as compared with the placebo group; the reversal of effects on Day 5 is suggestive of conditioned compensatory responses. Also, following the placebo on Day 5, desire to drink scores of the alcohol group were greater than those of the placebo group. The present data suggest that subjects exhibit conditioned compensatory responses when the environment signals alcohol availability. Results are consistent with Siegel's model of conditioned compensatory responses to repeated drug administration, and may help to account for some aspects of tolerance development and conditioned withdrawal.