Temperament and character dimensions differ in chronic post-surgical neuropathic pain and cold pressure pain

Psychobiological temperament and cognitive-evaluative character link to coping with chronic pain. The aim was to study possible independent role of temperament and character dimensions both in chronic and experimental pain in chronic post-surgical pain patients. This is a substudy of a previously published larger cohort of patients with intercostobrachial nerve injury after breast cancer surgery. We recruited 241 women who had been treated for breast cancer 4-9 years before. They had a surgeon-verified intercostobrachial nerve injury with or without chronic post-surgical neuropathic pain (CPSNP). The patients filled in the Temperament and Character Inventory (TCI), Pain Catastrophizing Scale (PCS), Hospital Anxiety and Depression Scale (HADS), and Brief Pain Inventory (BPI), and underwent the cold pressor test (CPT). 201 (83%) patients reported chronic pain and 135 (56%) met the criteria for CPSNP. Patients with CPSNP showed higher levels of Harm Avoidance (HA) temperament than non-CPSNP patients, which was associated with lower cold pain tolerance and greater increase of pain intensity during CPT. HA subscales Fear of Uncertainty and Fatigability contributed to a stronger pain experience. For character dimensions, CPSNP patients reported higher levels of Self-Transcendence (ST) and lower levels of Self-Directedness (SD) and Cooperativeness (CO) than non-CPSNP patients. Cold pain tolerance, intensity, or unpleasantness did not associate with character dimensions. Psychobiological temperament, but not character, is independently from other psychological factors associated with primary pain processing in an experimental pain setting. Patients with and without CPSNP showed different profiles on both temperament and character dimensions suggesting a combination of heightened emotional vulnerability and lowered personality adaptability in CPSNP patients. Character dimensions associated with clinical but not experimental pain. The study protocol was approved by the Ethics Committee of the Helsinki and Uusimaa Hospital District (reference number: 149/13/03/00/14). The study is registered in ClinicalTrials.gov (NCT02487524).