Antidepressants Effects on Pain in Parkinson Disease: A Systematic Review

Objective: Pain in Parkinson disease (PD) is complex as this symptom can be multifactorial in origin because deficits in dopaminergic but also other neurotransmitters are involved. Pain and depression are increasingly recognized to have clinical importance for the quality of life of people living with PD. This systematic review aims to summarize the existing evidence on the potential benefit of using prescribed antidepressants for decreasing or controlling pain associated with PD. Methods: PubMed databases were searched for relevant studies using keywords and our exclusion/inclusion criteria and targeting only randomized placebo-controlled trials for antidepressants in PD. Results: After screening 108 articles, only 3 focused articles were analyzed. Two of the included studies reported were on nortriptyline and paroxetine antidepressants. Unfortunately, included studies did not align in their outcome measures and did not directly compare the drug groups against each other or the placebo. Therefore, the complex nature of the unaligned outcome measures is inadequate for interpreting the efficacy of antidepressants in treating pain symptoms in PD. The third study focused solely on observing the effects of duloxetine but showed no favorable effects of this drug on pain. Conclusions: Prospective studieswith a direct comparison of antidepressants and placebo should be conducted, focusing on pain-related scales and questions to understand further the role of antidepressants in treating pain in PD.