Importance: Suicide risk may be increased in patients with Parkinson disease (PD), a common neurodegenerative condition. Mood disorders, especially depression, are prevalent in patients with PD who report suicidality.
Objective: To address inconsistent results from studies of suicidal ideation and behavior in patients with PD.
Data sources: The study team searched MEDLINE and Embase from inception to June 14, 2023, and further screened the bibliographies of relevant studies to ensure a comprehensive search.
Study selection: Original studies, published in English, discussing either suicidal ideation, behavior, or both in adults with PD were included. Accepted study designs included cross-sectional, case-control, and cohort studies. Studies that only included patients with PD after deep brain stimulation were excluded.
Data extraction and synthesis: This meta-analysis was conducted in line with the PRISMA guidelines. Two authors reviewed each study and extracted the data independently, with discrepancies referred to a third independent author.
Main outcomes and measures: Outcomes included the prevalence of suicidal ideation and behavior, measured as proportions, and the risk of suicidal behavior in patients with PD relative to controls, measured in both odds ratio (OR) and hazards ratio (HR).
Results: A total of 28 studies comprising 505 950 PD patients were included in the final analysis. The prevalence of suicidal ideation was evaluated in 14 studies (22.2%; 95% CI, 14.6-32.3) and suicidal behavior in 21 studies (1.25%; 95% CI, 0.64-2.41). Excluding 4 outliers, prevalence of suicidal behavior was significantly higher in prospective studies (1.75%; 95% CI, 1.03-2.95) than retrospective studies (0.50%; 95% CI, 0.24-1.01). Excluding 1 outlier, OR of suicidal behavior was pooled across 10 studies and significant (OR, 2.15; 95% CI, 1.22-3.78; P = .01). HR of suicidal behavior was assessed in 9 studies (HR, 1.73; 95% CI, 1.40-2.14; P < .001).
Conclusions and relevance: This meta-analysis involving more than 500 000 patients with PD found 22.2% and 1.25% of patients with PD to have suicidal ideation and behavior, respectively. Patients with PD had 2 times the risk of suicidal behavior than controls. Early recognition and management of suicidality in PD can help reduce mortality.