Reduced CSF neurotensin concentration in drug-free schizophrenic patients

The concentration of the tridecapeptide neurotensin was measured in CSF from 76 drug-free schizophrenic patients and 45 healthy controls. A highly significant difference was found between the two groups with lower concentration of neurotensin-like immunoreactivity in schizophrenic patients. Normalization of the lower concentrations was obtained in the same patients during ongoing neuroleptic treatment. The neurotensin concentrations in CSF was unrelated to sex, age, duration of the disorder or to previous neuroleptic treatment. Neurotensin levels did not differ between patients with or without a family history. A significant correlation was found between low neurotensin concentrations and decreased motor activity. No significant relationship was seen between the increment in CSF concentrations of neurotensin and clinical improvement during neuroleptic treatment. No significant correlation between CSF concentrations of neurotensin and HVA or 5-HIAA, major metabolites of dopamine and serotonin, respectively, could be demonstrated. However, in a limited number of the schizophrenic patients in this population, a significant correlation was seen between neurotensin and the noradrenaline metabolite MOPEG. The data support the hypothesis that certain schizophrenic patients may have a compromised CNS neurotensin system which might increase vulnerability for this disorder.