Patients with bipolar disorder appeared significantly more likely to develop Parkinson’s disease than the general population, according to results of a systematic review and meta-analysis published in JAMA Neurology.

“The main clinical implication of this review should be to underline that if patients with [bipolar disorder] present with parkinsonism features, this may not be drug induced and may recommend the investigation of [Parkinson’s disease],” Patricia R. Faustino, MD, of the Laboratory of Clinical Pharmacology and Therapeutics at the University of Lisbon in Portugal, and colleagues wrote. “To clinically distinguish parkinsonism from [Parkinson’s disease] in clinical practice, the use of functional neuroimaging methods may be of particular interest, as [Parkinson’s disease] classically presents with nigrostriatal degeneration [whereas] drug-induced parkinsonism does not.”