Negative expectancy as a mediating variable in marihuana intoxication.

Sixty experienced marihuana smokers participated in a study designed to assess the effect of a negative expectancy on marihuana intoxication. Two different environments, threat of shock and no-threat, were used under the drug conditions of marihuana and placebo. Ss came into the laboratory and adjusted a level of shock received at their fingertips, to a point of mild discomfort. Only those Ss in the threat groups were given the expectation that they would receive the shock at random times during the sessions. Results show that Ss in the marihuana threat group got subjectively less intoxicated, found the environment less pleasant, and yet had higher pulse rates than did Ss in the marihuana no-threat group. The results are discussed in terms of a cognitive component, and specifically that of labelling, in the determination of level of intoxication.