Nocturnal urinary cortisol excretion over a randomized controlled trial with paroxetine vs. placebo combined with relaxation training or aerobic exercise in panic disorder.

INTRODUCTION: Data on basal hypothalamo-pituitary-adrenomedullary (HPA) function over controlled treatment trials with serotonergic drugs in anxiety disorders are still rare. METHODS: 29 patients with panic disorder participating in a 10 week randomized, controlled trial (paroxetine vs. placebo with exercise or relaxation; N=60) collected urine for cortisol excretion over 3 consecutive nights before start and before termination of the treatment episode. Urinary cortisol was measured by radioimmunoassay. Efficacy measures were the Clinical Global Impression Scale (CGI) and the Panic and Agoraphobia Scale (P&A). 83% were female (p<.05 vs. males). 55% received additional aerobic exercise, and 45% relaxation. 55% received paroxetine treatment, and 45% placebo. Significantly fewer males received placebo treatment (p<.05). RESULTS: All subjects improved significantly. Cortisol excretion did not differ between treatment groups or at pre-/post measurements. Females showed a significantly higher variability of cortisol excretion compared to males, at pre-(p<.005) and post (p=.015) assessments. Males displayed a trend to lower basal HPA function at end of treatment (p=.08). HPA variability after treatment showed a trend to be higher in the paroxetine (p=.052) -who clinically improved significantly better- compared to the placebo group. No relationship between HPA activity and treatment response or with exercise was detected. DISCUSSION: HPA function shows significant gender differences, with females having a higher HPA function variability. Future studies on HPA function in treatment trials should address gender and medication effects.