Spontaneous afternoon plasma cortisol in depression

Area of Science:

• Endocrinology
• Psychiatry
• Clinical Neuroscience

Background:

• The hypothalamic-pituitary-adrenal (HPA) axis is frequently dysregulated in major depressive disorder.
• Plasma cortisol levels, a key marker of HPA axis activity, have been studied in relation to depression, but findings on diagnostic and prognostic value remain inconsistent.

Purpose of the Study:

• To investigate the relationship between spontaneous afternoon plasma cortisol levels and depression subtypes.
• To assess the potential of plasma cortisol as a predictor of treatment response in depressed patients.

Main Methods:

• Spontaneous plasma cortisol was measured in 74 hospitalized patients (56 endogenously and 18 non-endogenously depressed) between 15:00 and 18:00 h.
• Cortisol levels were analyzed in relation to depression type, severity, and treatment outcome with cyclic antidepressants.

Main Results:

• Afternoon plasma cortisol levels were significantly higher in depressed patients compared to post-recovery levels.
• Individual cortisol measurements correlated well with mean concentrations, with the strongest correlation observed between 16:00 and 17:00 h.
• Among endogenously depressed patients, non-responders to cyclic antidepressants alone exhibited significantly higher pretreatment cortisol levels than responders.

Conclusions:

• While spontaneous afternoon plasma cortisol may have limited diagnostic value for depression classification or severity.
• Elevated pretreatment afternoon plasma cortisol levels may serve as a predictor for treatment outcomes in endogenously depressed patients receiving cyclic antidepressants.