The effect of pain on stroop performance in patients with opiate dependence in sustained remission.

Objectives: We have demonstrated previously that former opiate-dependent subjects treated and detoxified from methadone maintenance therapy suffer deficits in neuropsychological performance and have abnormal pain thresholds. This study examined the impact of pain on the performance of the Stroop test, a well-known test of neuropsychological performance.

Methods: Twenty-three former opiate-dependent subjects treated and detoxified from methadone maintenance therapy and 24 comparison (COM) subjects without a history of opiate dependence were tested using the Stroop test under 2 conditions: Stroop under usual conditions and Stroop under painful conditions. The painful condition was induced using a Medoc Thermal Sensory Analyzer to deliver a heat stimulus at and below the subjects' pain threshold.

Results: COM subjects performed better than former opiate-dependent subjects, and females performed better than males on the Stroop under usual conditions. These differences were missing when the Stroop under painful conditions was performed. Analysis of these differences revealed that male former opiate-dependent subjects had a larger improvement in Stroop scores under the painful condition than male COM subjects or females of either group.

Conclusions: Performance on a neuropsychological test was adversely impacted by previous opiate addiction, and these effects seemed to be greater in males compared with females. Treated patients with opiate dependence showed improvement in Stroop test performance under painful conditions, and this improvement was greater in males than females.