Support for the mutual maintenance of pain and post-traumatic stress disorder symptoms

• Published in: Psychological medicine 2010-07, Vol.40 (7), p.1215-1223
• Main Authors: Liedl, A., O'Donnell, M., Creamer, M., Silove, D., McFarlane, A., Knaevelsrud, C., Bryant, R. A.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Adult and adolescent clinical studies; Aged; Anxiety disorders. Neuroses; Arousal; Arousal - physiology; Biological and medical sciences; Chronic Disease; Comorbidity; Female; Humans; Male; Mediator; Medical sciences; Middle Aged; Mind body relationship; mutual maintenance; Pain; Pain - diagnosis; Pain - epidemiology; Pain - psychology; Pain Measurement; Post traumatic stress disorder; Posttraumatic stress disorder; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Severity of Illness Index; Stress Disorders, Post-Traumatic - epidemiology; Stress Disorders, Post-Traumatic - psychology; structural equation modelling; Surveys and Questionnaires; Symptoms; Trauma; Traumatic life events; Young Adult
• ISSN: 0033-2917; 1469-8978
• DOI: 10.1017/S0033291709991310

Pain and post-traumatic stress disorder (PTSD) are frequently co-morbid in the aftermath of a traumatic event. Although several models attempt to explain the relationship between these two disorders, the mechanisms underlying the relationship remain unclear. The aim of this study was to investigate the relationship between each PTSD symptom cluster and pain over the course of post-traumatic adjustment. In a longitudinal study, injury patients (n=824) were assessed within 1 week post-injury, and then at 3 and 12 months. Pain was measured using a 100-mm Visual Analogue Scale (VAS). PTSD symptoms were assessed using the Clinician-Administered PTSD Scale (CAPS). Structural equation modelling (SEM) was used to identify causal relationships between pain and PTSD. In a saturated model we found that the relationship between acute pain and 12-month pain was mediated by arousal symptoms at 3 months. We also found that the relationship between baseline arousal and re-experiencing symptoms, and later 12-month arousal and re-experiencing symptoms, was mediated by 3-month pain levels. The final model showed a good fit [chi2=16.97, df=12, p>0.05, Comparative Fit Index (CFI)=0.999, root mean square error of approximation (RMSEA)=0.022]. These findings provide evidence of mutual maintenance between pain and PTSD.