Cortisol excretion during the defense reaction in humans

Twelve subjects with specific phobias were exposed to slides with a phobic or a neutral content while cortisol excretion, electrodermal activity, and distress-ratings were studied. Six subjects fearful of blood and mutilation, and six of snakes or spiders, were presented with two sets of ten different slides (phobic or neutral; 8-sec exposures, separated by 50-sec intervals) with the order of presentation balanced between days. Before and after each session, subjects rated feelings of distress, and urine samples were obtained for the determination of cortisol by radioimmunoassay. Electrodermal activity was recorded before and during slide presentation. Compared to neutral exposures, phobic slides elicited larger cortisol excretion, higher distress ratings, and greater skin-conductance responses with slower recovery. No differences between animal and blood and mutilation phobics were observed. Thus, humans having specific phobias exhibit pituitary-adrenal cortical arousal during the defense reaction elicited by slides of their phobic objects.