Affiliations: [a] Psychiatry Department, Department of Neurosciences, Hospital de Santa Maria, Lisbon, Portugal
| [b] Clínica Universitária de Psiquiatria e Psicologia Médica, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| [c] CNS – Campus Neurológico, Torres Vedras, Portugal
| [d] Laboratory of Clinical Pharmacology and Therapeutics, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| [e] Instituto de Medicina Molecular João Lobo Antunes, Lisbon, Portugal
| [f] Department of Psychiatry, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal
| [g] Department of Psychiatry, University of Cambridge, Cambridge, UK
Correspondence:
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Correspondence to: Prof. Joaquim J. Ferreira, MD, PhD, Laboratório de Farmacologia Clínica e Terapêutica, Faculdade de Medicina de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal. Tel.: +351 21 7802120; E-mail: jferreira@medicina.ulisboa.pt.
Abstract: Background:Depressive disorders are recognized as a common neuropsychiatric disorder of Parkinson’s disease (PD). Reported frequencies vary widely among studies and depend on the diagnostic criteria, the methods of ascertainment used, and the population sampled. Objective:We aimed to evaluate the frequency of depressive disorders in PD and to investigate the relationship with PD clinical variables. Methods:A systematic review and meta-analysis of observational studies (community-based, prospective and retrospective cohort, case-control, and cross-sectional studies) reporting the frequency of depressive disorders in PD patients. Results:Electronic database search wielded 3,536 articles; an additional 91 were identified through citation chaining. 163 full-text articles were assessed for eligibility. Of these, 49 met the inclusion criteria for our analysis. The pooled frequency of depressive disorders was 30.7% (95% confidence interval [CI] 25.6 to 36.2; I2 = 95%; 49 studies; combined n = 10,039). The pooled frequency of major depressive disorder was 14.0% (95% CI 10.5 to 18.5; I2 = 88%; 23 studies; combined n = 5,218). Subgroup/meta-regression analyses were conducted to investigate the relationship between frequency and study inclusion criteria, methodology used for diagnosis, and study design. We found a statistically significant correlation between study design and depressive disorders frequency (ranging from 8% in the community-based study to 44% in the retrospective studies) and a statistically significant positive correlation between mean baseline PD duration and major depressive disorder frequency. Conclusion:The current meta-analysis found a global frequency of depressive disorders of 30.7% and major depressive disorder of 14.0%. Study design influenced the frequency of depressive disorders in PD. Mean baseline PD duration and major depressive disorder frequency were positively correlated.
