Suicide in Parkinson's Disease

Suicide is a potentially preventable event. Suicidal ideation is common in Parkinson's disease (PD), but literature on completed suicides is scarce. In this case-control study, we compared the clinical characteristics of PD subjects who completed suicide (case) with those who died from natural causes (control).

PD patients from the National Neurosciences Institute's movement disorders database from 2002 till 2012 were identified. The database was linked to the Singapore National Registry of Disease Office for mortality information, and suicide deaths were confirmed with the coroner's office. The demographic and clinical variables were compared between the cases and controls and the significant factors were further analyzed using logistic regression analysis.

During the study period, 366 deaths were recorded and suicide accounted for 11 deaths. Ten subjects with suicide deaths with complete clinical information were compared with randomly selected 30 PD subjects who had died from natural causes. PD suicide patients were younger (65.9 vs. 74.48 years), had less comorbidities (CWI: 2.6 vs. 4.63), better cognition (MMSE: 25.75 vs. 21.36), lower 'ON' UPDRS motor scores (20.83 vs. 41.63), lower H &Y stage (2.16 vs. 3.86), and higher use of Entacapone than the PD non-suicide group.

Suicide is potentially preventable tragedy. PD patients with the identified clinical characteristics should be closely monitored for suicide ideations. Motor fluctuation is a treatable factor in such patients and should be aggressively managed.