To determine frequency of lifetime suicidal behavior in Parkinson disease (PD). 

PD is associated with depression and demoralization, but it is unknown whether suicidality is increased in PD. 

PD and non-PD controls completed online surveys, assessing lifetime suicidality with the Suicidal Behavior Questionnaire-revised (SBQ-R). PD was defined by self-report and having a neurologist PD diagnosis or taking levodopa. Depression was assessed using the Brief Lifetime Depression Scale. Suicide risk was high if SBQ-R was >= 7. Questions included “Have you ever thought about or attempted to kill yourself?” Responses included: “No”, “It was a passing thought.”; “I have had a plan to kill myself.”; “I have attempted to kill myself.” Demoralization was assessed using the Kissane Demoralization Scale and Diagnostic Criteria for Psychosomatic Research.

178 PD and 182 control subjects were comparable in age (64.9±8.1 years), gender (51.4% women), income (83.6% middle or high income), and education (87.5% college or higher). PD patients were no more likely than controls to have high suicide risk (12.9% vs 15.9%; p=0.42) and significantly less likely to have had a lifetime suicide attempt or plan (2.8% vs 7.7; p=0.03). This was despite PD patients having significantly higher prevalence of lifetime depression (40.4% vs. 20.9%; p<0.0001) and demoralization (23.0% vs. 11.0%; p=0.002). SBQ-R score was equivalent in PD and controls (4.4±2.2 vs. 4.5±2.1; p=0.67). In the overall cohort, SBQ-R score was significantly positively associated with demoralization (1.32 units 95% CI [0.72,1.93]; p<0.0001), depression (0.91 units [0.40,1.41]; p=0.0004), and past drug abuse history, and marginally negatively with PD (-0.43 units [-0.86,0.004]; p=0.053). For PD, SBQ-R was significantly positively associated with demoralization [1.91 units (0.83,2.99)], drug abuse, and being widowed, but not with depression [-0.75 units(-1.7,0.24)].