The cortisol awakening response in bipolar illness: a pilot study.

Area of Science:

• Endocrinology
• Neuroscience
• Psychiatry

Background:

• Abnormal cortisol regulation is linked to mood disorders.
• The hypothalamo-pituitary-adrenocortical (HPA) axis plays a crucial role in stress response and mood regulation.
• A heightened salivary cortisol awakening response may indicate enduring HPA axis dysregulation.

Purpose of the Study:

• To investigate the salivary cortisol awakening response in clinically stable bipolar disorder (BD) patients with known long-term HPA axis dysregulation.
• To determine if the free cortisol response to waking is elevated in BD patients, irrespective of their Dexamethasone Suppression Test (DST) results.
• To explore the potential of the cortisol awakening response as a biomarker for HPA axis dysregulation.

Main Methods:

• Salivary cortisol levels were measured every 15 minutes during the first hour of waking in 18 clinically stable, lithium-responsive BD patients.
• Additional salivary samples were collected at 3:00 PM and 8:00 PM.
• The free cortisol response to waking was assessed using these samples.

Main Results:

• Clinically stable BD patients demonstrated a significantly enhanced salivary cortisol response to waking compared to control subjects (P < 0.03).
• Cortisol levels at 30 minutes post-waking were significantly higher than normative data (P < 0.001).
• This enhanced response was observed even in patients with normal DST values.

Conclusions:

• The free cortisol response to waking can reflect persistent HPA axis dysregulation in BD patients, even when clinically stable and on lithium.
• The salivary cortisol awakening response may serve as a practical and promising biomarker for identifying individuals at risk for or predisposed to mood disorders.
• This easy-to-administer test could be valuable in genetic studies of mood disorder susceptibility.