Effects of oxazepam on anxiety: implications for Fowles' psychophysiological interpretation of Gray's model.

The present dose-response study investigated the effects of the benzodiazepine oxazepam (Serax) on anxiety as measured by autonomic and self-report indices in a nonclinical sample. Given Fowles' (1980, 1988) theory that electrodermal activity primarily reflects the activity of the behavioral inhibition system (BIS) while heart rate primarily reflects the activity of the behavioral activation system (BAS), we predicted that electrodermal indices of anxiety would be more affected by oxazepam than heart rate. Psychophysiological and self-report measures were recorded prior to and following a speech stressor in subjects given placebo (n = 17), 15 mg oxazepam (n = 19), and 30 mg oxazepam (n = 17). Anxiolytic effects were found during stressed state as measured by skin conductance level but not heart rate or self-reported anxiety. Furthermore, the anxiolytic effects of oxazepam were noted only during the stressful phases of the experiment. The results are viewed as supportive of Fowles' motivational interpretation of the distinction between heart rate and electrodermal responding.