Stress hormones during flooding therapy and their relationship to therapy outcome in patients with panic disorder and agoraphobia.

In spite of excessive fear during a panic attack, studies have found no or little evidence for an activation of cortisol during natural panic attacks. Whether this phenomenon is related to psychopathology or outcome of psychotherapy is unknown. In this study, 10 patients with panic disorder and agoraphobia were treated with cognitive behavioural therapy including 3 in-vivo exposures (flooding) to individual phobic situations. Before, during and after exposure, the level of subjective fear was assessed and blood was collected simultaneously. Cortisol and ACTH were analysed from plasma. Ten matched healthy control subjects went through the same procedure. Fear and stress hormones during exposure were compared in patients and controls as well as related to therapy outcome at the end of therapy and 2 follow-ups in patients. Results showed that the concentrations of cortisol and ACTH did not significantly increase during exposure. Patients' cortisol concentrations were higher than those of controls at baseline and during exposure, while ACTH concentrations were comparable before and during exposure, and even lower than those of controls at recovery. Cortisol concentrations were moderately but consistently correlated to therapy outcome, i.e. patients with least cortisol release during exposure profited least from therapy. The study showed that a lack of stimulation of the HPA system at repeated confrontation with the phobic situation was related to therapeutic outcome. Mechanisms of action via the influence of cortisol on extinction learning or the inhibition of central excitatory neurotransmission are conceivable.