Periodic leg movements and neuroleptic-induced parkinsonism in patients with schizophrenia

The incidence of periodic leg movements (PLM) during sleep is markedly lower in middle aged schizophrenic patient than expected in this age group. This finding may be linked to high dopaminergic levels in subcortical areas reported in schizophrenic patients. Neuroleptic medication decreases dopaminergic activity and in the present study we predicted that patients with extrapyramidal symptoms will be more likely to exhibit PLM during sleep. METHOD: We compared sleep and PLM during sleep in two groups of schizophrenic patients that were comparable in terms of pharmacolocial treatment but differed in the development of neuroleptic-induced parkinsonism (NIP). Results: 22 consecutive patients with the diagnosis of schizophrenia and a monotherapy with haloperidol participated in the study. During treatment twelve patients developed NIP, while the other 10 patients did not experience any extrapyramidal-motor side effects. NIP-patients had a significantly shorter sleep duration (392±63 vs. 453±26 min), a higher number of nocturnal awakenings (26±16 vs. 14±9) and an increased percentage of wakefulness compared with the symptom free patients (16±9% vs. 8±4%). NIP-patients also exhibited a significant higher number of PLM per hour during sleep (12±9 vs. 5±3). Conclusion: Lowering of dopamine levels by neuroleptic medications that affect the motor system is associated with the emergence of PLM in schizophrenic patients.