Affective modulation of pain in substance-dependent veterans.
OBJECTIVE
Prior work suggests that positive affect inhibits pain while negative affect facilitates it. The current study sought to determine whether: 1) affective modulation of pain extends to a patient population; 2) cocaine and alcohol dependence influences the pattern of modulation; and 3) affective modulation of pain is mediated by changes in arm temperature.


METHODS
Thirty-seven participants with and without substance dependence (14 alcohol, 13 cocaine, 10 none) attended three experimental sessions intended to induce emotions (negative, neutral, positive) by picture-viewing. Following emotion-induction, participants were asked to submerge their arm in 33 degrees F water and keep it there until they reached tolerance. During submersion, pain ratings were made on a mechanical visual analog scale (M-VAS).


METHODS
Latency from submersion to first movement of the M-VAS (pain threshold) and latency to arm removal (pain tolerance) were measured. Arm temperature and manipulation checks for emotion-induction (corrugator electromyogram, heart rate, skin conductance, self-report) were also recorded.


RESULTS
Manipulation checks confirmed that targeted affective states were achieved. Pain threshold and tolerance were higher after viewing pleasant pictures than after unpleasant ones. Although arm temperature did vary based on the affect induced, analyses suggested that temperature did not influence pain outcomes.


CONCLUSIONS
Affect modulates pain perception in patients and does not appear to be mediated by changes in arm temperature. Additionally, pain modulation was not significantly influenced by cocaine or alcohol dependence. These data are encouraging, because they suggest that nonpharmacological methods of pain modulation may be effective in substance-dependent individuals.
Rhudy
Jamie L
JL
The University of Tulsa, 600 South College, Tulsa, OK 74104, USA. jamie-rhudy@utulsa.edu
Dubbert
Patricia M
PM
Parker
Jefferson D
JD
Burke
Randy S
RS
Williams
Amy E
AE
D000328:Adult; D000437:Alcoholism / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D001008:Anxiety Disorders / Q000209:etiology* / Q000523:psychology / Q000628:therapy*; D001521:Behavior Therapy / Q000379:methods; D019970:Cocaine-Related Disorders / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D003080:Cold Temperature / Q000009:adverse effects; D004644:Emotions / Q000187:drug effects / Q000502:physiology*; D005239:Fear / Q000502:physiology / Q000523:psychology; D006240:Happiness; D006801:Humans; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009433:Neural Inhibition / Q000502:physiology; D010146:Pain / Q000503:physiopathology / Q000523:psychology*; D059408:Pain Management; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D012201:Reward; D012725:Sexual Behavior / Q000502:physiology / Q000523:psychology; D019966:Substance-Related Disorders / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D016896:Treatment Outcome; D014728:Veterans / Q000523:psychology