The finding: Patients with early Parkinson’s disease (PD) scored significantly higher on all psychiatric scales and scored significantly lower on the Addenbrook’s Cognitive Examination-Revised (ACE-R). Psychiatric scales included: Neuropsychiatic Inventory (NPI), Hamilton Depression and Anxiety Scales (HDRS and HADS), Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), and Scales for Outcomes in Parkinson’s Disease-Psychiatric Complications (SCOPA-PC). Versus controls, early PD patients (patients diagnosed less than two years prior to enrollment in study) showed significantly more apathy (33% vs 4%), depression (22% vs 5%), and anxiety (7% vs 1%). Daytime and nighttime sleepiness along with apathy was predictive of early PD.

Strengths and weaknesses: Patients and controls were evenly matched re demographics, exclusion criteria were adequate in screening out many confounders (including later stage PD, patients receiving pharmacotherapy, patients with significant psychopathology, etc.), and participants received an extensive battery of psychometric tests. However, enrollment bias was likely present, the study was cross-sectional and therefore did not assess longitudinal changes, and it was non-randomized and non-blinded.

Relevance: This study lends credence to the idea of monitoring (and treating) neuropsychiatric symptoms (NPS) at all stages of PD. Additionally, this study reminds the C-L psychiatrist not to overlook the likelihood of increased disease burden, decreased quality of life, and other clinically relevant outcomes due to comorbid NPS (apathy, anxiety, depression, fatigue, and cognitive decline) in this population.