LETHAL CATATONIA AND NEUROLEPTIC MALIGNANT SYNDROME - A DOPAMINE-RECEPTOR SHUT-DOWN HYPOTHESIS

Background. Lethal catatonia and neuroleptic malignant syndrome (NMS) have been suggested to have a common neurochemical cause. We hypothesi se that both conditions may be due to a sudden and massive blockade of dopamine neurotransmitters. Method. NMS was diagnosed in psychotic in -patients treated with neuroleptics if four features were present: dif fuse severe rigidity, altered level of consciousness, hyperpyrexia and autonomic instability. Results. Over three years, five NMS cases were diagnosed. Two presented with catatonic features and were diagnosed a s acute reactive psychosis. Their neuroleptic doses were small, arguin g for a particular sensitivity in these two cases. Conclusion. The sen sitivity of two patients with catatonic features who developed NMS wit h small doses of neuroleptics supports a common neurochemical basis fo r the two conditions.