Decreased corticotropin-releasing hormone (CRH) concentrations in the cerebrospinal fluid of eucortisolemic suicide attempters

Abstract

Several lines of evidence suggest a dysregulation of the adrenocortical (HPA) system with hypersecretion of CRH is associated with suicidal behavior. However, controversial results have emerged from the determination of corticotropin-releasing hormone (CRH) concentrations in the lumbar cerbrospinal fluid (CSF) of suicide attempters probably due to methodological differences. We simultaneously measured CRH concentrations in the CSF and in the plasma of 41 psychiatric in-patients with different diagnoses (affective disorder, schizophrenia, personality disorders, adjustment disoder, substance abuse) and eight neurological control subjects. We also measured plasma cortisol concentrations because data from animal experiments suggest that cortisol may influence CSF CRH concentrations. The major finding was that patients who attempted suicide prior to admission had significantly lower CSF CRH concentrations than psychiatric patients without suicidal behavior. CRH concentrations were significantly higher in the CSF than in plasma in both, psychiatric patients and neurological control subjects. There was no significant difference between suicide attempters and patients with acute suicidal ideations. The latter group showed a trend towards lower CSF CRH concentrations compared with the neurological control subjects. Patients with affective disorder alone as well as patients with multiple diagnoses, but not schizophrenic patients, showed significantly lower CSF CRH concentrations than neurological control subjects. Plasma CRH and plasma cortisol concentrations did not differ among diagnostic groups or between suicide attempters vs. non-attempters. Further studies with more homogenous samples, drug-free patients and with simultaneous assessment of various parameters of the HPA system are warranted.