Whether chronic pain is medically explained or not does not moderate the response to cognitive-behavioural therapy

To determine whether pain-related treatment outcomes, following an online Cognitive Behavioural Therapy (CBT) intervention for chronic pain, were moderated by the pain etiology of a medically explained or unexplained origin. Data were available from 471 participants who completed the online pain management program between March 2013 and August 2014. Participants' pain symptoms were classified as being medically explained symptoms (MES: n = 292) or medically unexplained symptoms (MUS: n = 222) via analysis of clinical data. Outcome variables were pain-related disability, average pain intensity, depression and anxiety. Moderation analyses were non-significant for all dependent variables. Between group differences (CBT and control) were larger for depression in those classified with MES, compared with MUS (MUS: mean change = −3.50 [95% CI = −4.98 to −2.22]; MES: mean change = −5.72 [95% CI = −7.49 to −4.09]). However, between group differences were small for pain intensity (MUS: mean change = −0.03 [95% CI = −0.83 to 0.81]; MES: mean difference = −1.12 [95% CI = −1.84 to 0.40]). The therapeutic outcomes examined in this study associated with an online CBT program do not appear to be altered by whether the participants' pain symptoms are medically explained or unexplained. •Psychological therapy for chronic pain improves mood and pain-related disability.•Medically explained and unexplained symptoms benefit equally from therapy.•Addressing pain-related distress is a key component in multidisciplinary therapy.