Noradrenergic function and HPA axis dysregulation in suicidal behaviour

Area of Science:

• Neuroscience
• Psychiatry
• Biomarkers of Suicide Risk

Background:

• Noradrenergic system and Hypothalamic-Pituitary-Adrenal (HPA) axis dysregulation are implicated in suicide risk.
• Previous studies show inconsistent links between cerebrospinal fluid (CSF) 3-methoxy-4-hydroxphenylglycol (MHPG) and suicide risk.
• Non-suppression in the dexamethasone suppression test (DST) is associated with elevated suicide risk in depressed patients.

Purpose of the Study:

• To investigate the association between CSF MHPG levels, HPA axis function, and suicidal behavior.
• To determine if combined CSF MHPG and HPA axis markers can predict suicide risk.

Main Methods:

• Study included 51 mood disorder inpatients.
• Collected CSF MHPG levels and performed DST.
• Followed patients for cause of death to identify suicide victims.

Main Results:

• Suicide victims (n=9) had significantly lower CSF MHPG and baseline plasma cortisol compared to survivors.
• Receiver Operating Characteristic (ROC) analysis using both CSF MHPG and baseline cortisol yielded a positive predictive value of 44% and an area under the curve of 0.88 for suicide prediction.

Conclusions:

• Lower CSF MHPG levels are associated with increased suicide risk.
• Combined assessment of the noradrenergic system (via CSF MHPG) and HPA axis function may enhance the prediction of suicidal behavior.