Quetiapine improves visual hallucinations in Parkinson disease but not through normalization of sleep architecture: results from a double-blind clinical-polysomnography study.

Polysomnographic studies of Parkinson's disease (PD) patients with visual hallucinations (VH) usually reveal short, fragmented rapid eye movement (REM) sleep, with lower sleep efficiency and reduced total REM sleep. Quetiapine has been demonstrated in open-label trials to be effective for the treatment of insomnia and VH in PD. To confirm quetiapine's efficacy in improving VH, and to determine whether the mechanism was due to its effect on REM sleep architecture, we performed a pilot, double-blind, placebo-controlled study.