Post-dexamethasone cortisol as a predictor for the efficacy of electroconvulsive therapy in depressed inpatients.

Background: Although several variables have been studied as a possible predictor for the efficacy of ECT, results regarding hypercortisolism have been inconsistent. This prospective study evaluates the relation between pre-treatment cortisol levels and the efficacy of ECT in a population of drug-free inpatients with severe major depression.

Methods: At the inpatient depression unit, 18 patients meeting the DSM-IV criteria for depressive disorder, and with scores of at least 18 on the 17-item Hamilton Rating Scale for Depression (HAM-D), were treated with bilateral ECT twice weekly. The HAM-D evaluated depression severity and was performed within 3 days prior to ECT, weekly during the course of ECT, and within 3 days after the last treatment. The outcome criterion was defined a priori as the change on the HAM-D score. Salivary cortisol was assessed within 3 days prior to ECT at two time points, followed by 0.5 mg dexamethasone ingestion. The following day, salivary cortisol was again assessed at two time points. The generalized linear model was used to assess the relation between salivary cortisol levels and reduction in HAM-D score as continuous variables.

Results: Higher levels of salivary cortisol at 9 AM after 0.5 mg dexamethasone ingestion are associated with a greater reduction in HAM-D score (B = -0.279, 95% CI: -0.557 to -0.01, s.e. = 0.13, p = 0.049; R square = 0.23; adjusted R square = 0.13).

Conclusion: This study suggests that higher levels of post-dexamethasone salivary cortisol at 9 AM are predictive of ECT efficacy.