Low Cerebrospinal Fluid Neuropeptide Y Concentrations in Posttraumatic Stress Disorder

Background: Neuropeptide Y (NPY), a peptide neurotransmitter that regulates stress and anxiety, has been proposed to be a stress resilience factor in humans. Posttraumatic stress disorder (PTSD) is a stress-related anxiety disorder. We hypothesized that central nervous system NPY is dysregulated in PTSD and sought to redress the absence of central NPY data in the disorder. Methods: We determined morning NPY concentrations in cerebrospinal fluid (CSF) from 10 male subjects with chronic combat-related PTSD and from 13 healthy men. Neuropeptide Y-like immunoreactivity was measured by enzyme immunoassay (EIA). Results: As compared with the normal comparison subjects, PTSD patients had significantly lower concentrations of CSF neuropeptide Y (mean CSF NPY was 360.0 +/- 17.7 pg/mL in control subjects but only 233.6 +/- 28.7 pg/mL in PTSD patients [p = .0008]). Adjustments for age and body mass index (BMI) still revealed a highly significant reduction in CSF NPY in the PTSD group (p = .003). Conclusions: Men with combat-related PTSD have low CSF concentrations of the putative resiliency hormone NPY, possibly related to the disorder or to extreme stress exposure per se.