Patients With Parkinson's at Elevated Risk for Suicidal Thoughts, Behavior

Adults with Parkinson's disease (PD) are twice as likely to engage in suicidal behavior as the general population, results of a large meta-analysis show.

Given that up to half of patients with PD suffer from depression and anxiety, physicians should maintain a "high index of suspicion" for early recognition and management of suicidality, write the investigators, led by Eng-King Tan, MD, of Duke-NUS Medical School in Singapore.

"Management of both medical, such as sleep disorders, and psychosocial risk factors, such as feelings of loneliness, hopelessness, and depressed mood, could be useful in lowering suicide risk in patients with PD," they add.

The study was published online November 13 in JAMA Neurology.

Suicide Risk Neglected in PD?

The analysis included 505,950 patients with PD across 28 cross-sectional, case-control, and cohort studies.

Across 14 studies, the prevalence of suicidal ideation in patients with PD was 22.2% (95% CI, 14.6 - 32.3). In a sensitivity analysis excluding three outliers, the prevalence of suicidal ideation was higher at 24% (95% CI, 19.1 - 29.7).

Across 21 studies, the prevalence of suicidal behavior was "substantial" at 1.25% (95% CI, 0.64 - 2.41), the authors report. The 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 to 1.01).

Across 10 studies, the likelihood of suicidal behavior was about twofold higher among patients with PD than general population controls (odds ratio [OR], 2.15; 95% CI, 1.22 - 3.78; P = .01). Across nine studies, the hazard ratio for suicidal behavior was 1.73 (95% CI, 1.40 - 2.14; P < .001).

There was no evidence of sex-related differences in suicidal behavior, although the analysis was limited by the paucity of data, the researchers note. 

They note the quality of included studies was generally high, although eight of them did not explicitly identify and adjust for confounders.

Higher Rate of Mood, Anxiety Disorders

Commenting on the research for Medscape Medical News, Paul Nestadt, MD, with Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, said this analysis reiterates what several reviews have found over the past few years, including his own.

"In general, rates of mood and anxiety disorders are much higher in PD than in other dementias, such as Alzheimer's disease. This is reason enough to allocate resources to the mental health care of those diagnosed with PD, and to pay special attention to at risk periods, such as early in the diagnosis, when suicide rates seem to be higher in dementias in general," said Nestadt, who wasn't involved in the study.

He noted that research has shown that suicides among people with PD are more likely to involve a firearm — likely because people with PD are more likely to be over age 65 and to be male — "both huge risk factors for firearm suicide."

"Therefore, it is essential that caregivers be aware of the risks posed by firearms in the homes of people suffering from Parkinson's or other dementias. It is the clinician's responsibility to inform families of this risk, but it is all too often neglected," Nestadt said.

Support for the study was provided in part by the National Medical Research Council. Tan reported honoraria from Eisai and Elsevier outside the submitted work. Nestadt reports no relevant financial relationships.