Beyond the stigma of methadone maintenance treatment : neurocognitive recovery in individuals with opiate use disorders

Background: Studies of cognitive functioning in drug addiction have shown consistent impairments among substance dependent populations. Several attempts to highlight the neurocognitive recovery of former opioid dependent individuals who are stabilised on methadone, have resulted in contradictory conclusions. The aim of this study is to compare the cognitive function of recovering opioid dependent individuals on methadone maintenance treatment to those who are not on methadone treatment, relative to healthy controls. -- Methods: The Montreal Cognitive Assessment Tool was administered to three groups of participants: 22 former opioid dependents receiving methadone maintenance treatment, 21 former opioid dependents withdrawn from all opiates and 22 healthy controls without a history of illicit substance dependence. The specific cognitive domains tested include executive function, visuospatial skills, naming, attention, language, abstraction, delayed recall and orientation. -- Results: Visuospatial skills and executive function were significantly improved with methadone. The language domain appears to be significantly impaired in both opioid dependent groups with a strong negative correlation to the duration of dependency. Participants who had stopped methadone were significantly impaired in all other aspects of cognition tested apart from naming and orientation when compared to healthy controls. Participants on methadone did not significantly differ in the other areas of cognition when compared to controls. -- Conclusions: Methadone treatment appears to be associated with an improvement in cognitive function in opioid dependent individuals. Thus, methadone may facilitate public health by ensuring compliance of opioid dependent individuals to their treatment plan with fewer relapse rates and mitigation of risky behaviours.peer-reviewe