The Influence of Parkinson's Disease on Depression Through Structural Equation Modeling

ObjectiveTo analyze and compare the magnitudes of nonmotor symptoms in depressed individuals with and without Parkinsons Disease. MethodsDownloaded in January 2023, symptoms and characteristics of depressed individuals with and without Parkinsons Disease were extracted from the longitudinal study Fox Insight. The directed acyclic graph theory was used to represent causal relationships and to determine the associations between nonmotor symptoms, depression, and Parkinsons Disease. The 2-PL and the Rasch models were used to better fit the data and identify the items consistent with the assumptions. ResultsDropped interests and activities was the item that was of greatest impact and most characteristic for depressed individuals both with and without PD. Double vision was the item of least difficulty while an additional item of significant impact was Preferred to stay at home. Education attainment had little to no impact on depression severity in individuals with and without PD. ConclusionsDropped interests and activities was most severe within both populations. Relatedly, an increased average number of leisure hours was associated with greater depression severity. Overall, as an individuals depression worsens, there is an overall upward trend in the severity of their nonmotor symptoms. We recommend additional analyses on the strength of relationships between these neurologic disorders and nonmotor symptoms.