Drug preference and mood in humans: preference for d-amphetamine and subject characteristics

Forty-five normal, young, adult volunteers participated in a nine-session experiment. During the first four sessions, they received alternately 5 mg d-amphetamine or placebo. During the next five sessions, they chose between amphetamine and placebo. On the basis of the choice results, subjects retrospectively were divided into the following three groups: (1) five of five drug choices (N = 16); (2) four of five drug choices (N = 12); and (3) 0--3 of five drug choices (N = 17). There was an overall average of 3.76 drug choices per subject. These groups were compared by demographic characteristics, drug use history, and several personality measures, but none predicted drug choice. However, subjects who chose drug on every occasion had significantly higher predrug scores on the anxiety, depression, and confusion subscales of the Profile of Mood States (POMS). The functional relationship between initial dysphoria and consistent amphetamine choosing remains an intriguing question.