Prospective evaluation of circulatory levels of catecholamines and serotonin in neuroleptic malignant syndrome

Objective: Neuroleptic malignant syndrome (NMS) may be associated with a dy sregulation of the catecholaminergic and serotonergic systems. The objectiv e of the present study was to evaluate prospectively the circulatory levels of serotonin (5-HT), epinephrine (E) and dopa in patients suffering from N MS. Method: Platelet-poor plasma (PPP) levels of serotonin, epinephrine and dop a in eight NMS patients were measured twice: in the acute state and in the state of remission. Results: PPP dopa concentration was significantly lower in acute NMS state compared to the remission state (P = 0.023). In contrast, PPP E level was s ignificantly higher (P = 0.019) in the acute NMS state and PPP 5-HT concent rations in the acute state tended to be higher than those at remission (P = 0.078). 5-HT/dopa ratio was significantly higher in the acute NMS (P = 0.0 15). Conclusion: These results may reflect reduction in dopaminergic function an d increase in adrenergic and serotonergic activity in the acute NMS state.