Psychomotor retardation in depression linked to increased Parkinson's risk

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medRxiv Published April 28, 2026 Medically reviewed April 28, 2026 Study authors: Morrin, H.; Badenoch, J. B.; Burchill, E.; Fayosse, A.; Singh-Manoux, A.; Shotbolt, P.; Zandi, M. S.… DOI ↗ By Dr. Ji-eun Park, MD · Brain, Mind & Pain

Key Takeaway

Consider psychomotor retardation in depression as a potential marker for prodromal Parkinson's disease.

This retrospective cohort study analyzed data from a large mental health service in London, UK, including 6327 individuals diagnosed with depression at age 40 or over, followed from 2007 to 2023. The exposure was the presence of psychomotor retardation, which occurred in 2402 (38.0%) of the sample.

The primary outcome was development of subsequent Parkinson's disease. After adjustment, the hazard ratio for Parkinson's disease in those with psychomotor retardation was 1.43 (95% CI 1.02 - 2.01, p = 0.04), indicating a statistically significant increased risk. The relationship could not be solely explained by misdiagnosis.

Safety and tolerability data were not reported. The study's limitations were not explicitly stated, but as a retrospective cohort, confounding and selection bias are possible. The findings suggest that psychomotor retardation may serve as a marker of prodromal Parkinson's disease in patients with depression.

Clinicians should consider this association when evaluating older patients with depression and psychomotor retardation, but should not overstate the predictive value. Further prospective studies are needed to confirm these findings.

Study Details

Study typeCohort

Sample sizen = 6,327

EvidenceLevel 3

PublishedApr 2026

View Original Abstract ↓

Background: Depression is associated with an increased risk of subsequent Parkinson's disease. Neuroimaging studies suggest a neurobiological overlap in mechanisms underlying Parkinson's disease and psychomotor retardation in depression. Our aim was to investigate whether, among individuals with depression, the presence of psychomotor retardation was associated with the development of subsequent Parkinson's disease. Methods: In a retrospective cohort study, electronic healthcare records from individuals diagnosed with depression at age 40 or over in a large mental health service in London, UK were examined for the presence of psychomotor retardation. Linkage to general hospital records was used to ascertain diagnoses of Parkinson's disease between 2007 and 2023. Cox regression was used to compare the hazard of Parkinson's disease in individuals with depression with and without psychomotor retardation. Results: Among 6327 patients with depression, 2402 (38.0%) had psychomotor retardation. The adjusted hazard ratio for development of Parkinson's in those with psychomotor retardation was 1.43 (95% CI 1.02 - 2.01, p = 0.04). Secondary analyses demonstrated a significant difference in psychomotor retardation incidence at least 10 years before Parkinson's diagnosis. Conclusions: Psychomotor retardation in later-life depression is associated with increased risk of subsequent Parkinson's diagnosis over an extended period of time, suggesting that the relationship cannot solely be explained by misdiagnosis. Psychomotor retardation may therefore serve as a marker of prodromal Parkinson's disease.