Cerebrospinal Fluid Neuropeptide Y-like Immunoreactivity Correlates with Impulsive Aggression in Human Subjects

Background: Neurochemical studies have pointed to a modulatory role in human aggression for a number of central neurotransmitters; some (e.g., serotonin) appear to play an inhibitory role, while others (e.g., vasopressin) appear to play a facilitator role in the modulation of aggression. While recent animal studies of neuropeptide Y (NPY) have suggested a facilitator role for central NPY in the modulation of aggression, no human studies of central NPY have yet been reported regarding aggression. Methods: Basal lumbar cerebrospinal fluid (CSF) was obtained from 60 physically healthy subjects with personality disorder (PD) (n = 40) and from healthy volunteers (n = 20). These samples were then assessed for CSF NPY-like immuno reactivity (NPY-LI) and other neuro transmitter-related species in CSF and correlated with measures of aggression and impulsivity. Results: Cerebrospinal fluid NPY-LI was higher in PD subjects compared with healthy volunteers and in subjects with intermittent explosive disorder compared with those without intermittent explosive disorder. In PD subjects, CSF NPY-LI was directly correlated with composite measures of aggression and impulsivity and a composite measure of impulsive aggression. Group differences in CSF-NPY-LI concentration were accounted for by measures of impulsive aggression. Conclusions: These data suggest a direct relationship between CSF NPY-immunoreactivity concentration and measures of impulsive aggression in human subjects. This adds to the complex picture of the central neuromodulatory role of impulsive aggression in human subjects.