Absent cortisol response during stressful exposure therapy in patients with obsessive-compulsive disorder

Exposure with response prevention (ERP) is the most effective treatment for patients with obsessive-compulsive disorder (OCD), but associated with considerable temporary stress during initial therapy sessions. Thus, it may serve as an interesting model to characterize neuroendocrine response to a psychological stimulus in these patients. However, so far only few studies have assessed hypothalamic-pituitary-adrenocortical function during ERP and results are inconsistent. In a pilot stuy we repeatedly measured salivary cortisol and subjective units of distress (SUD) on two consecutive afternoons in 15 patients with OCD during the first session of ERP and on a prior comparison day. Expectedly, SUD were significantly higher before and during ERP versus the comparison day (means 49.8 vs. 31.4 and 72.6 vs. 34.0, resp.). However, salivary cortisol concentrations were statistically indistinguishable between ERP and comparison condition before, as well as during and after ERP. This response pattern to ERP in OCD patients is not sufficiently explicable and needs further research. Our findings resemble congruent results in patients with panic disorder. Hypotheses on psychological and neurobiological backgrounds of this unexpected regulatory pattern will be discussed. The possible impact of cortisol response on extinction learning during ERP will be be speculated on and investigated more closely in this ongoing study.