Disability from pain directly correlated with depression in Parkinson's disease

Parkinson's disease (PD) is a progressively debilitating disorder resulting in reduced quality of life (QoL). Along with the motor symptoms of PD, non-motor symptoms of PD such as pain, restless leg syndrome (RLS) depression also occur. These exacerbate the worsening QoL and must be promptly diagnosed and treated. The objective of this study was to determine the relationship between pain severity, walking, general activity and work (WAW) and rapid eye movements (REM) dimensions of pain interference, and disability with depression and RLS in PD.

120 patients with PD and 120 controls were evaluated for depression using the Hospital Anxiety and Depression Scale (HADS-D). Pain severity and interference was measured using Brief Pain Inventory (BPI). REM and WAW dimensions of pain were also measured. The Pain Disability Index (PDI) was used to assess the disabling effects from chronic pain.

The study found a statistically significant direct correlation between the BPI, PDI and PD. A significant direct correlation was also found for depression and pain in PD. No association as found between RLS and PD; RLS was not a confounding factor.

Based on these findings, we conclude that pain interference, severity of pain and disability from pain is directly correlated with depression in PD. We also discern that these symptoms of PD are not independent of each other. We cannot establish a causal relationship between any of these variables. Prompt recognition and treatment of pain and depression is valuable in preserving the quality of life in PD.