Do antidepressants have an analgesic effect in psychogenic pain and somatoform pain disorder? A meta-analysis.
OBJECTIVE
A significant amount of evidence indicates that some antidepressants have an analgesic effect. We wished to determine whether this analgesic effect could be demonstrated in studies that had used antidepressants for the treatment of pain in patients diagnosed with psychogenic pain or somatoform pain disorder. Meta-analysis was used for this purpose.


METHODS
All randomized, placebo-controlled antidepressant treatment studies of patients diagnosed with psychogenic pain disorder or somatoform pain disorder were isolated. These studies were reviewed and relevant statistics were coded. For each study, a single p value for the drug/placebo comparison was found or calculated for pain change scores from pretreatment to completion of treatment. The z scores and effect sizes were calculated for each study, followed by a calculation of an overall z score and effect size.


RESULTS
Eleven studies fulfilled the inclusion and exclusion criteria for this meta-analysis. The combined difference showed that antidepressants decreased pain intensity in patients with psychogenic pain or somatoform pain disorder significantly more than placebo (z = 5.71, p<.0001). The overall effect size was large (mean = 0.48) and ranged from 0 to 0.91.


CONCLUSIONS
The results indicate that, in patients diagnosed with psychogenic pain or somatoform pain disorder, antidepressant treatment resulted in a reduction in pain that was significantly greater than that of placebo. Possible explanations for these results are discussed.
Fishbain
D A
DA
Department of Psychiatry, University of Miami School of Medicine, University of Miami Comprehensive Pain & Rehabilitation Center, at South Shore Hospital, South Miami Beach, Florida 33319, USA. cprc@umcprc.com
Cutler
R B
RB
Rosomoff
H L
HL
Rosomoff
R S
RS
D000700:Analgesics / Q000627:therapeutic use*; D000928:Antidepressive Agents / Q000627:therapeutic use*; D002908:Chronic Disease; D006801:Humans; D010146:Pain / Q000188:drug therapy / Q000523:psychology*; D010147:Pain Measurement; D016032:Randomized Controlled Trials as Topic; D013001:Somatoform Disorders / Q000188:drug therapy / Q000523:psychology*
D000700:Analgesics; D000928:Antidepressive Agents