A Portrait of Anxiety and Depression in Parkinson's Disease: Prevalence, Clinical Correlates, and Treatment Gaps

BACKGROUND: Non-motor symptoms (NMS), specifically anxiety and depression are major drivers of disability in Parkinson's disease (PD). Prevalence estimates remain inconsistent because of differences in population samples, diagnostic criteria, and symptom overlap, contributing to underdiagnosis and undertreatment. OBJECTIVES: This retrospective, cross-sectional study examined the prevalence, comorbidity, and clinical correlates of anxiety and depression using dimensional severity scales and multivariate modeling. METHODS: We retrospectively analyzed de-identified records from 1221 patients assessed by a single neurologist specializing in PD patient care. Mood symptom severity was evaluated using Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) criteria. Logistic regression models identified associated factors for relevant anxiety (BAI ≥13) and depression (BDI ≥14). RESULTS: Clinically relevant anxiety (42%) and depression (30%) and anxiety-depression comorbidity (24%) were found to be consistent with previous estimates, with a high prevalence of mild depression (33%). Regression models identified sleep disturbance as a primary associated factor for both mood symptoms. Functional impairments involving hygiene, walking, swallowing, sensory complaints, and speech were associated with one or both mood symptoms. Left lower-extremity bradykinesia and right-sided tremor were associated with both mood symptoms. Significant "treatment" and "remission" gaps were also observed, as prescriptions for anxiolytics and antidepressants were significantly associated with relevant anxiety and depression. CONCLUSIONS: These findings highlight pervasive diagnostic and therapeutic gaps and the relationship between mood symptoms and functional disability. The limited efficacy of pharmacological monotherapy underscores the need for multi-dimensional tools and integrated treatment approaches to improve recognition and management of mood symptoms in PD.