Lithium and peripheral nervous system function in manic-depressive patients

Influence of lithium on peripheral nervous function was evaluated by measuring 
of electrophysiological parameters in two 
groups of psychiatric patients (20 lithium treated
 and 20 affective-psychotic patients without the
 lithium treatment) and a group of 20 healthy
volunteers. Lower amplitudes of M waves (p <
 0.015) and sensory neurograms (p < 0.020) on 
stimulation of the median nerve have been 
found in both groups of patients. On peroneal
 nerve stimulation lower M wave amplitudes have been found only in the group of lithium
 treated patients (p < 0,055). No significant differences in conduction parameters of motor and 
sensory fibers were demonstrated. Our results
 demonstrate subclinical involvement of motor 
and sensory axons in affective-psyhotic patients, which is only slightly more pronounced in 
lithium treated patients. We suggest that lithium
 (within therapeutic plasma concentrations) is
 just one among the factors leading towards 
minor axonopathy in psychiatric patients.