High frequency of Depressive Disorders and Suicidal Phenomena in Late-Stage Parkinson´s Disease - A Cross-Sectional Study.

Background: Depressive disorders (DD) are widely recognized as one of the most frequent neuropsychiatric disorders in Parkinson´s disease. Patients with late-stage Parkinson´s disease (LSPD) continue to be a neglected population, and little is known about DD frequency in LSPD.

Objectives: To determine the frequency of DD in LSPD patients through a clinical diagnostic interview (CDI) and according to diagnostic DSM- 5 criteria. Secondary objectives were to determine the predictive ability of depressive scales to detect DD, to identify potential predictors of DD in LSPD and, to evaluate suicidal phenomena in LSPD.

Methods: A cross-sectional study including LSPD patients (≥7 years from symptom onset and Hoehn and Yahr scale score >3 or a Schwab and England scale score <50% in the ON condition) was conducted. Patients were subjected to psychiatric, neurological, and neuropsychological evaluations. Six depression scales were applied.

Results: 92 LSPD patients were included. 59.78% of LSPD patients had a current diagnosis of DD according to CDI, 38.04% patients had a diagnosis of major depressive disorder, and 21.72% non-major depressive disorder. Suicidal ideation was present in 36.96% of patients. All applied scales were able to detect depressive disorders.

Conclusions: More than half of LSPD patients met DD diagnostic criteria and over one-third were diagnosed with major depressive disorder. Overall, the LSPD population seem to have a unique clinical phenotype regarding the frequency and features of DD, whose early identification and treatment could improve the quality of life of patients and caregivers.