title: Evidence for acute central sensitization to prolonged experimental pain in posttraumatic stress disorder.
abstract: BACKGROUND
  Post-traumatic stress disorder (PTSD) and pain have a well-documented high comorbidity; however, the underlying mechanisms of this comorbidity are currently poorly understood. The aim of this psychophysical study was to investigate the behavioral response to a prolonged suprathreshold pain stimulus in subjects with combat-related PTSD and combat controls (CC) for clinical evidence of central sensitization.
  
  
  METHODS
  Ten male subjects with current PTSD related to combat and 11 CC male subjects underwent baseline quantitative sensory testing (QST), temporal pain summation, and psychological profiling followed by an intramuscular injection of capsaicin into the quadriceps muscle.
  
  
  RESULTS
  There was no significant between-group difference for the initial maximal pain response or an initial pain reduction for the first 15 minutes postinjection on QST or pain ratings. However, we observed significantly higher scores in the PTSD group for the second 15 minutes postinjection on both pain intensity and pain unpleasantness ratings. Assessment of temporal summation to repetitive pressure stimuli showed significantly higher subjective pain in the PTSD group.
  
  
  CONCLUSIONS
  These findings are consistent with a significantly higher degree of acute central sensitization in individuals with PTSD. Increased acute central sensitization may underlie increased vulnerability for developing pain-related conditions following combat trauma.
authors.affiliation: Center of Excellence for Stress and Mental Health, San Diego, California, USA; VA San Diego Healthcare System, San Diego, California, USA; Department of Anesthesiology, University of California San Diego, San Diego, California, USA.
authors.forename: Tobias
authors.initials: T
authors.lastname: Moeller-Bertram
authors.forename: Irina A
authors.initials: IA
authors.lastname: Strigo
authors.forename: Alan N
authors.initials: AN
authors.lastname: Simmons
authors.forename: Jan M
authors.initials: JM
authors.lastname: Schilling
authors.forename: Piyush
authors.initials: P
authors.lastname: Patel
authors.forename: Dewleen G
authors.initials: DG
authors.lastname: Baker
mesh_terms: D059787:Acute Pain / Q000453:epidemiology / Q000523:psychology*; D000328:Adult; D001007:Anxiety / Q000453:epidemiology / Q000523:psychology; D002211:Capsaicin / Q000008:administration & dosage; D058443:Catastrophization / Q000453:epidemiology / Q000523:psychology; D059333:Central Nervous System Sensitization; D059350:Chronic Pain / Q000453:epidemiology / Q000523:psychology*; D015897:Comorbidity; D003863:Depression / Q000453:epidemiology / Q000523:psychology; D019317:Evidence-Based Medicine; D006801:Humans; D006930:Hyperalgesia / Q000523:psychology; D008297:Male; D017288:Pain Threshold / Q000523:psychology*; D011312:Pressure / Q000009:adverse effects; D011788:Quality of Life; D018689:Sensory System Agents / Q000008:administration & dosage; D013313:Stress Disorders, Post-Traumatic / Q000453:epidemiology / Q000523:psychology*; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D018689:Sensory System Agents; D002211:Capsaicin
keywords: Capsaicin; Central Sensitization; Experimental Pain; PTSD; Quantitative Sensory Testing