Reframing chronic pain as a disease, not a symptom: rationale and implications for pain management.

Chronic pain is a common public health problem that has a detrimental impact on patient health, quality of life (QoL), and function, and poses a substantial socioeconomic burden. Evidence supports the redefinition of chronic pain as a distinct disease entity, not simply a symptom of injury or illness. Chronic pain conditions are characterized by three types of pain pathophysiology (i.e. nociceptive, neuropathic, and centralized pain/central sensitization) influenced by a cluster of coexisting psychosocial factors. Negative risk/vulnerability factors (e.g. mood or sleep disturbances) and positive resilience/protective factors (e.g. social/interpersonal relationships and active coping) interact with pain neurobiology to determine patients' unique pain experience. Viewing chronic pain through a biopsychosocial lens, instead of a purely biomedical one, clinicians need to adopt a practical integrated management approach. Thorough assessment focuses on the whole patient (not just the pain), including comorbidities, cognitive/emotional/behavioral characteristics, social environment, and QoL/functional impairment. As for other complex chronic illnesses, the treatment plan for chronic pain can be developed based on pain subtype and psychosocial profile, incorporating pharmacotherapy and self-management modalities. Preferred pharmacologic treatment of conditions primarily associated with nociception (e.g. osteoarthritis) includes acetaminophen and non-steroidal anti-inflammatory drugs, whereas preferred pharmacologic treatment of conditions primarily associated with neuropathy or central sensitization (e.g. fibromyalgia) includes tricyclic compounds, serotonin-norepinephrine reuptake inhibitors, and α2δ ligands. Education, exercise, cognitive behavioral therapy, and many other non-pharmacological approaches, alone or combined with pharmacotherapy, have been shown to be effective for any type of pain, although they remain underutilized due to lack of awareness of their benefits and reimbursement obstacles.