Cortisol as a predictor of psychological therapy response in anxiety disorders—Systematic review and meta-analysis

• Does cortisol predict psychotherapy response in anxiety disorders?
• Comprehensive systematic review and meta-analysis.
• No relationship between basal (unstimulated) cortisol and treatment response.
• Higher cortisol during exposure predicted better responses in systematic review.
• Meta-analysis did not confirm this.

BackgroundAlthough psychotherapy generally is effective in anxiety disorders, many patients are treatment-resistant. At the same time, some patients with anxiety disorders show alterations in the hypothalamic-pituitary-adrenal (HPA) axis, one of the major stress-responsive systems. Since raised levels of the end product of the HPA axis, cortisol, adversely affect cognition, we hypothesised that more pronounced alterations in cortisol levels would be associated with a less favourable response to psychotherapy. More specifically, the higher patients’ basal levels and the lower their levels during exposure, the less likely we expected them to profit from treatment.MethodsWe systematically searched the Cochrane Library, EMBASE, MEDLINE, and PsycINFO to review the literature and perform a meta-analysis on the relationship between pre-treatment cortisol and psychotherapy response. Records were included if they studied patients with any anxiety disorder undergoing psychotherapy, with a pre-treatment cortisol and a post-treatment symptom measure. Correlation coefficients were extracted for meta-analyses.ResultsWe identified six studies (N = 274). No relationship between patients’ basal cortisol and post-treatment symptoms was found (p = 0.981). The systematic review showed higher cortisol during exposure sessions to predict better outcomes. Meta-analysis did not confirm this (p = 0.603).ConclusionsBasal cortisol did not seem to predict psychological therapy responses in patients with anxiety disorders. By contrast, the current state of research is equivocal in terms of whether higher cortisol concentrations during exposure sessions are linked with better treatment outcomes, and more research is needed to investigate this.