Reduced orexin levels in the cerebrospinal fluid of suicidal patients with major depressive disorder

Eur Neuropsychopharmacol. 2007 Sep;17(9):573-9. doi: 10.1016/j.euroneuro.2007.01.005. Epub 2007 Mar 7.


Orexins are neuropeptides selectively expressed in a small number of neurons in the lateral-posterior hypothalamus. We measured orexin-A in the cerebrospinal fluid (CSF) of 66 patients with major depressive disorder (MDD), dysthymia and adjustment disorder after a suicide attempt. Blood samples confirmed that the patients were free from antidepressive and neuroleptic medication at the time of the lumbar punctures. CSF levels of orexin-A were significantly lower in patients with MDD than in patients with adjustment disorder and dysthymia. Orexin correlated significantly with CSF levels of somatostatin, delta sleep inducing peptide-like immunoreactivity (DSIP-LI) and corticotrophin releasing factor (CRF), but not with leptin or vasopressin. Plasma levels of thyroid-stimulating hormone (TSH) were not reduced in MDD patients, and did not correlate with CSF-orexin. Our results suggest that suicidal patients with MDD have distinct neurobiological features, involving compromised levels of hypothalamic peptides regulating the state of arousal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjustment Disorders / cerebrospinal fluid
  • Adult
  • Age Factors
  • Corticotropin-Releasing Hormone / metabolism
  • Delta Sleep-Inducing Peptide / metabolism
  • Depressive Disorder, Major / cerebrospinal fluid*
  • Depressive Disorder, Major / psychology*
  • Down-Regulation / physiology*
  • Dysthymic Disorder / cerebrospinal fluid
  • Female
  • Humans
  • Intracellular Signaling Peptides and Proteins / cerebrospinal fluid*
  • Male
  • Middle Aged
  • Neuropeptides / cerebrospinal fluid*
  • Orexins
  • Radioimmunoassay
  • Sex Factors
  • Somatostatin / metabolism
  • Statistics, Nonparametric
  • Suicide*


  • HCRT protein, human
  • Intracellular Signaling Peptides and Proteins
  • Neuropeptides
  • Orexins
  • Somatostatin
  • Delta Sleep-Inducing Peptide
  • Corticotropin-Releasing Hormone