Altered pain processing in veterans with posttraumatic stress disorder.

CONTEXT: Posttraumatic stress disorder (PTSD) is a chronic and debilitating anxiety disorder. Several brain areas related to pain processing are implicated in PTSD. To our knowledge, no functional imaging study has discussed whether patients with PTSD experience and process pain in a different way than control subjects. OBJECTIVE: To examine neural correlates of pain processing in patients with PTSD. DESIGN: The experimental procedure consisted of psychophysical assessment and neuroimaging with functional magnetic resonance imaging. Two conditions were assessed during functional magnetic resonance imaging in both experimental groups, one condition with administration of a fixed temperature of 43 degrees C (fixed-temperature condition) and the other condition with an individual temperature for each subject but with a similar affective label equaling 40% of the subjective pain intensity (individual temperature condition). SETTING: Academic outpatient unit in a department of military psychiatry in collaboration with an imaging center at a psychiatric hospital. PARTICIPANTS: Twelve male veterans with PTSD and 12 male veterans without PTSD were recruited and matched for age, region of deployment, and year of deployment. MAIN OUTCOME MEASURES: Changes in functional magnetic resonance imaging blood oxygenation level-dependent response to heat stimuli, reflecting increased and decreased activity of brain areas involved in pain processing. RESULTS: Patients with PTSD rated temperatures in the fixed-temperature assessment as less painful compared with controls. In the fixed-temperature condition, patients with PTSD revealed increased activation in the left hippocampus and decreased activation in the bilateral ventrolateral prefrontal cortex and the right amygdala. In the individual temperature condition, patients with PTSD showed increased activation in the right putamen and bilateral insula, as well as decreased activity in the right precentral gyrus and the right amygdala. CONCLUSIONS: These data provide evidence for reduced pain sensitivity in PTSD. The witnessed neural activation pattern is proposed to be related to altered pain processing in patients with PTSD.

Neural correlates of antinociception in borderline personality disorder.

CONTEXT: A characteristic feature of borderline personality disorder (BPD) is self-injurious behavior in conjunction with stress-induced reduction of pain perception. Reduced pain sensitivity has been experimentally confirmed in patients with BPD, but the neural correlates of antinociceptive mechanisms in BPD are unknown. We predicted that heat stimuli in patients with BPD would activate brain areas concerned with cognitive and emotional evaluation of pain. OBJECTIVE: To assess the psychophysical properties and neural correlates of altered pain processing in patients with BPD. DESIGN: Case-control study. SETTING: A university hospital. PARTICIPANTS: Twelve women with BPD and self-injurious behavior and 12 age-matched control subjects. INTERVENTIONS: Psychophysical assessment and blood oxygen level-dependent functional magnetic resonance imaging during heat stimulation with fixed-temperature heat stimuli and individual-temperature stimuli adjusted for equal subjective pain in all the participants. MAIN OUTCOME MEASURE: Blood oxygen level-dependent functional magnetic resonance imaging signal changes during heat pain stimulation. RESULTS: Patients with BPD had higher pain thresholds and smaller overall volumes of activity than controls in response to identical heat stimuli. When the stimulus temperature was individually adjusted for equal subjective pain level, overall volumes of activity were similar, although regional patterns differed significantly. Patient response was greater in the dorsolateral prefrontal cortex and smaller in the posterior parietal cortex. Pain also produced neural deactivation in the perigenual anterior cingulate gyrus and the amygdala in patients with BPD. CONCLUSION: The interaction between increased pain-induced response in the dorsolateral prefrontal cortex and deactivation in the anterior cingulate and the amygdala is associated with an antinociceptive mechanism in patients with BPD.

Elevated pain thresholds correlate with dissociation and aversive arousal in patients with borderline personality disorder.

In addition to reduced pain perception, patients with borderline personality disorder (BPD) show higher pain thresholds under subjective stress conditions as compared with non-stress conditions. However, the correlation between symptoms of stress and pain thresholds has not been investigated so far. Using a new and convenient methodology, electric stimulation, we expected higher pain and detection thresholds in patients with BPD than in to healthy controls as well as a positive correlation between pain thresholds and symptoms of stress (aversive arousal and dissociation) in BPD patients. Twelve female patients with BPD and twelve healthy controls were included in the study. Electric stimulation was applied on the right index finger, and detection and pain thresholds were assessed by gradually intensifying the stimuli. We found significantly elevated pain thresholds in patients with BPD as compared with healthy controls, but no difference between patients and controls in detection thresholds. In patients, a significant positive correlation was revealed between pain thresholds and dissociation as well as between pain thresholds and aversive arousal. Besides demonstrating a close correlation between pain thresholds and symptoms of stress in patients with BPD, this study replicated earlier findings of reduced pain perception in patients with BPD. Measuring electric pain thresholds is a valid and reasonable method for larger studies.

Neuroimaging of pain perception in Dutch veterans with and without posttraumatic stress disorder: preliminary results.

This article presents initial data on the application of a pain protocol in posttraumatic stress disorder (PTSD) to assess the neural circuitry that is involved in the disorder, with a special interest in the role of the anterior cingulate cortex (ACC). Preliminary analysis demonstrated a specific and differentiated role for the ACC. Fixed affects analysis demonstrated that stimuli subjectively perceived as more painful resulted in increased activation of the caudal ACC, whereas less painful stimuli resulted in increased activation of the rostral ACC in both groups.