The traumatised chronic pain patient—Prevalence of posttraumatic stress disorder - PTSD and pain sensitisation in two Scandinavian samples referred for pain rehabilitation
Authors: Andersen Tonny Elmose , Andersen Per Grünwald , Vakkala Merja Annika , Elklit Ask 
Published: January 2012

Abstract

Introduction
Correctly identifying chronic pain patients with posttraumatic stress disorder (PTSD) is important because the comorbidity of a chronic pain condition and PTSD is found to compromise treatment success. In addition, the existence of PTSD is associated with pain sensitisation, elevated levels of pain, and disability. Furthermore, the diagnostic criteria for PTSD has changed dramatically in the last two decades which has had a profound impact on the reported prevalence rates of PTSD in chronic pain samples. To our knowledge, no study has employed the DSM-IV criteria for estimating the prevalence of PTSD in chronic pain patients referred consecutively for multidisciplinary pain rehabilitation.

Aim
The aim of the present study was to assess the prevalence of significant traumatic stressors and PTSD in chronic pain patients referred consecutively to multidisciplinary pain rehabilitation. We wanted to investigate whether specific pain diagnoses were more related to PTSD than others. Moreover, we investigated the possible association of altered sensory processing (hypersensitivity or hyposensitivity) and PTSD.

Methods
Data were collected from two Scandinavian multidisciplinary pain centres (Denmark and Finland). All patients referred consecutively were assessed for PTSD and sensitisation at admission. A total of 432 patients were assessed, of which 304 (DK, N =220, female n = 144; FIN, N=84, female n = 44) were admitted and consented to participate. All patients had to be diagnosed with a non-malign chronic pain condition lasting for at least 6 months (median = 6.0 years). The Harvard Trauma Questionnaire was employed to measure PTSD symptoms, using the DSM-IV criteria. To measure altered sensory processing, anaesthetists performed quantitative sensory testing on admission. Patients were asked to report if cold, brush, and pinprick mechanical stimulation resulted in decreased or increased sensation or pain.

Results
stimulation resulted in decreased or increased sensation or pain. Results: A high prevalence of PTSD was found in both consecutive samples. Using the DSM-IV criteria, 23% fulfilled the criteria for a possible PTSD diagnosis. There were no gender differences in PTSD. The three most reported traumatic events: traffic accidents, serious illness personally or in the family, and the actual loss of someone, were reported as the primary traumatic events by almost 50% of those with PTSD. No particular pain diagnosis was significantly related to PTSD. However, hypersensitivity to cold and hyposensitivity to brush were significantly associated with PTSD.

Discussion
The prevalence of PTSD in the present study was 23%. Earlier studies finding a lower prevalence rate of PTSD may reflect the use of older diagnostic criteria for PTSD or other estimates, for instance PTSD symptom cut-off scores.

Conclusion
The study emphasised the importance of screening all chronic pain patients for PTSD at admission for pain rehabilitation, using up to date diagnostic tools.

Implications
Untreated PTSD may exacerbate or maintain the pain condition and negatively affect outcome of pain rehabilitation.