REPRINTED WITH PERMISSION OF IASP – PAIN 164 (2023) 2425–2434: Pain in Parkinson disease: mechanistic substrates, mainclassification systems, and how to make sense out of them

Parkinson disease (PD) affects up to 2% of the general population older than 65 years and is a major cause offunctional loss. Chronic pain is a common nonmotor symptom that affects up to 80% of patients with (Pw) PD bothin prodromal phases and during the subsequent stages of the disease, negatively affecting patient’s quality of lifeand function. Pain in PwPD is rather heterogeneous and may occur because of different mechanisms. Targetingmotor symptoms by dopamine replacement or with neuromodulatory approaches may only partially control PD---related pain. Pain in general has been classified in PwPD according to the motor signs, pain dimensions, or painsubtypes. Recently, a new classification framework focusing on chronic pain was introduced to group different typesof PD pains according to mechanistic descriptors: nociceptive, neuropathic, or neither nociceptive nor neuropathic.This is also in line with the International Classification of Disease-11, which acknowledges the possibility of chronicsecondary musculoskeletal or nociceptive pain due to disease of the CNS. In this narrative review and opinionarticle, a group of basic and clinical scientists revise the mechanism of pain in PD and the challenges faced whenclassifying it as a stepping stone to discuss an integrative view of the current classification approaches and howclinical practice can be influenced by them. Knowledge gaps to be tackled by coming classification and therapeuticefforts are presented, as well as a potential framework to address them in a patient oriented manner.