Nicholas et al. PAIN 160 (2019) 28–37
Chronic primary pain is a new diagnosis in the ICD-11 classification for chronic pain that is intended to embrace a number of poorly understood conditions while avoiding obscure and potentially laden terms such as “somatoform,” “nonspecific,” or “functional.”
Chronic primary pain syndromes can be conceived as health conditions in their own right, whereas in the other 6 groups of chronic pain conditions (chronic secondary pain syndromes), pain may be considered a symptom of some other underlying diseases. Complex Regional Pain syndrome (CRPS) is one of the key second level diagnosis on this new classification. This classification has clear treatment and management implications: a multimodal approach that addresses the contributing psychological, social, and biological contributors is expected to lead to better outcomes for patients with CPP diagnoses of at least moderate severity, relative to unimodal interventions alone.
For more details please refer to Pain (2019)