Reduced Orexin Levels in the Cerebrospinal Fluid of Suicidal Patients With Major Depressive Disorder

Orexin-A was measured in the cerebrospinal fluid of 66 patients with major depressive disorder, dysthymia, & adjustment disorder after a suicide attempt. Cerebrospinal fluid levels of orexin-A were significantly lower in patients with major depressive disorder than in patients with adjustment disorder & dysthymia. Results suggest suicidal patients with major depressive disorders have distinct neurobiological features, involving compromised levels of hypothalamic peptides regulating the state of arousal. (37 refs.)