Associations between baseline cortisol and trajectory of symptom improvement in depressed adolescents receiving psychological therapy.
BACKGROUND: Cortisol hypersecretion in depressed adolescents and adults is associated with more persistent illness and may signal a lower response to psychological therapies. A meta-analysis of small and heterogenous studies demonstrated that higher pre-treatment basal cortisol levels were associated with poorer response specifically to psychological therapy for depression. The objective of this study was to investigate the relationship between both morning and evening salivary cortisol levels and response to psychological therapy in depressed adolescents participating in one large randomised controlled trial. METHODS: We tested the association between morning and evening salivary cortisol levels at baseline and improvement in depressive symptoms in response to psychological therapies in depressed adolescents at 6 time points: baseline, 6, 12, 36, 52- and 86-weeks post-randomisation, using the self-reported Mood and Feelings Questionnaire (MFQ). RESULTS: High evening cortisol was associated with a slower initial decline in depressive symptoms (cortisol x quadratic time p = .022); however it was not associated with total change in depressive symtoms over the whole course of the study. Morning cortisol was not associated with change in depressive symptoms. These effects were not significantly different across the three psychological therapies. LIMITATIONS: Results may not generalize to adolescents receiving other treatments (medication) or no treatment, and may not generalize to adults. Only a minority of eligible participants collected valid cortisol samples. CONCLUSIONS: Higher pretreatment evening cortisol may impair a depressed adolescent's ability to use psychological therapy.