Autonomic nervous system and risk factors for vascular disease. Effects of autonomic unbalance in schizophrenia and Parkinson's disease.

Alterations of the cardiovascular system and of the glucose and lipid metabolism can represent important factors of vascular risk. The autonomic nervous system, through its two efferent branches, the parasympatheticcholinergic and the sympathetic-adrenergic, plays an important role in the control of the cardiovascular activity and of the glucose and lipid metabolism, and its impaired working can interfere with these functions. An increased sympathetic activity and an increased frequency of diabetes, dyslipidemia, hypertension and obesity have been reported in untreated schizophrenic patients, and a further worsening of these vascular risk factors has been signalled as a side effect of treatment with neuroleptic drugs. The opposite is observed in Parkinson's disease, where the reduced autonomic activity induced by the illness is associated with a decreased frequency of vascular risk factors, and their occurrence is further reduced by the treatment with dopaminergic drugs.