Plasma homovanillic acid, noradrenaline and psychotic symptoms in chronically medicated schizophrenic in patients

Objective: The authors investigated plasma homovanillic acid (HVA) levels and noradrenaline (NA) in chronically medicated schizophrenic inpatients. Methods: The subjects were 55 inpatients who were diagnosed according to the DSM-IV criteria for schizophrenia. Nine normal subjects were compared to the patient group. Each patient gave informed consent for the research involved in this study. Psychiatric symptoms were assessed using the BPRS. Results: (1) The medicated schizophrenic inpatients had significantly greater plasma NA levels, and higher but nonsignificant plasma HVA levels than the normal subjects. (2) In patients, there was a positive but nonsignificant correlation between the plasma NA levels and positive symptomatology. In contrast, plasma HVA levels were not correlated with either positive or negative symptomatology. Conclusion: On the basis of these results, we hypothesize that, mainly because of their catecholaminergic dysfunction, there is an increase in plasma NA and a tendency for increased plasma HVA in patients with chronic schizophrenia, regardless of long-term neuroleptic medication.