NEUROPSYCHOLOGICAL PERFORMANCE AND PLASMA-CORTISOL, ARGININE-VASOPRESSIN AND OXYTOCIN IN PATIENTS WITH MAJOR DEPRESSION

Background. The aim of the study was to search for the existence of, a nd define, a possible relationship between performance in neuropsychol ogical tests and baseline concentrations of plasma cortisol, vasopress in and oxytocin in medication-free patients with a major depressive ep isode. Methods. Measures of depression and anxiety were obtained and a neuropsychological battery was presented. Blood for neuropeptide anal ysis was drawn by venepuncture at 8.00, 16.00 and 23.00 h. Results. Th e melancholic patients performed less well on the neuropsychological b attery than did the non-melancholic patients, but these differences co uld be accounted for by the severity of the illness. Global intellectu al functioning was negatively correlated with mean baseline plasma con centrations of cortisol. Patients with high mean plasma vasopressin co ncentrations remembered more auditory presented words in the delayed r ecall test and produced more intrusions in the visual word learning li st than did patients with low or normal mean plasma vasopressin concen trations. No association was found between neuropsychological performa nce and plasma concentrations of oxytocin. Conclusions. Our findings s upport the hypothesis that elevated baseline plasma cortisol concentra tions are related to cognitive impairment in depressed patients and th e hypothesis that the neuropeptide vasopressin independently enhances memory, directly or indirectly through increasing arousal and attentio n.