November 08, 2019
People with bipolar disorder appear to be at greater risk of developing Parkinson disease compared with the general population, according to results from a systematic review and meta-analysis published online 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 disease,” researchers wrote. “To clinically distinguish parkinsonism from Parkinson disease in clinical practice, the use of functional neuroimaging methods may be of particular interest, as Parkinson disease classically presents with nigrostriatal degeneration while drug-induced parkinsonism does not.”
To assess the association between bipolar disease and a subsequent diagnosis of idiopathic Parkinson disease, researchers evaluated data from 7 studies on the likelihood of developing Parkinson disease with and without bipolar disorder. The studies spanned more than 4.3 million participants.
According to the meta-analysis, a previous diagnosis of bipolar disorder significantly increased the likelihood of later developing idiopathic Parkinson disease.
“These results may invite many questions from people with bipolar disorder and their physicians,” researchers wrote. “Are all subtypes of bipolar disorder at an equal risk? Is the risk present even when the diagnosis is made at a young age? What are the roles of lithium and antipsychotics? We would be interested in seeing these questions examined in large prospective cohorts of patients with bipolar disorder.”
Faustino PR, Duarte GS, Chendo I, et al. Risk of developing Parkinson disease in bipolar disorder: a systematic review and meta-analysis [published online October 14, 2019]. JAMA Neurol. doi: https://doi.org/10.1001/jamaneurol.2019.3446