High reactivity of the cortisol awakening response predicts positive treatment outcome in heterogeneous depressed patients completing an alternate milieu inpatient program

Objective: Delineating clinically meaningful subgroups within heterogeneous depressed populations is a major challenge. As outlined in the Research Domain Criteria Strategy, biomarkers may help to empirically classify such patients. Following this basic strategy, the current pilot study examined whether the cortisol awakening response (CAR) following admission to hospital predicts treatment response in heterogeneous depressed patients completing a 4-week alternate milieu inpatient program.

Methods: The Alternate Inpatient Milieu program at the Centre for Addiction and Mental Health is composed of both individual-based and group-based programming designed to promote a recovery-oriented, collaborative treatment environment. The current sample consisted of 25 consecutive patients with various forms of complex/chronic depression who completed the full program. Saliva samples were collected at 0, 30 and 60 min after awakening on 2 consecutive days following admission. Linear regressions controlling for baseline depression scores were used to assess whether the CAR AUCg (area under the curve ground) and/or AUCi (area under the curve increase) at admission predicted the change in depression scores from admission to discharge based on the Quick Inventory of Depressive Symptoms scale.

Results: The CAR AUCi, but not the CAR AUCg, at admission significantly predicted treatment response over the 4-week hospital stay. In these naturalistic patients with major depressive disorder, high CAR reactivity as assessed using the AUCi was associated with a better treatment response (t=2.20; df=2,24; P=.039). The CAR was easy to implement and well accepted by patients and staff.

Conclusion: This pilot study suggests that CAR reactivity at admission may help to identify a subgroup of depressed patients most likely to respond clinically to a 4-week alternate milieu inpatient program.