LITHIUM AND PERIPHERAL NERVOUS-SYSTEM FUNCTION IN MANIC-DEPRESSIVE PATIENTS

Introduction - Lithium salts are widely used in treatment of affective disorders, but lithium may cause electrophysiologically detectable ch anges in peripheral nervous system even with lithium concentrations wi thin recommended therapeutic limits. The risk of lithium treatment aga inst other risks to peripheral nervous system in psychiatric patients with affective psychoses was tested in our study. Material and method - Electrophysiologic parameters of motor and sensory peripheral nerve fibre function were measured in two age-matched groups of psychiatric patients (20 lithium-treated and 20 affective psychotic patients witho ut lithium treatment) and a group of 20 healthy age-matched volunteers . Results - Lower amplitudes of M waves (p < 0.015) and sensory nerve action potentials (p < 0.020) on stimulation of the median nerve have been found in both groups of patients. On peroneal nerve stimulation l ower M wave amplitudes have been found only in the group of lithium-tr eated patients (p < 0.055). No significant differences in conduction p arameters of motor and sensory fibres were demonstrated. Conclusion - Our results demonstrate subclinical involvement of motor and sensory a xons in affective-psychotic patients, which is only slightly more pron ounced in lithium-treated patients. We suggest that lithium (within th erapeutic plasma concentrations) is just one among the factors leading towards minor axonopathy in psychiatric patients.