Buprenorphine- and Methadone Maintenance Treatment: Influence on Aspects of Cognitive and Memory Performance

Our randomized study investigated neurocognitive performance, such as working memory, verbal and figural memory, executive functions and psychomotor speed of opioid-dependent patients within a permanent maintenance treatment programme. Our results indicate that buprenorphine preserve cognitive functions better than methadone, at least when benzodiazepine comedication is used. Buprenorphine-treated patients showed significantly better results compared to methadone patients in the verbal memory performance, and this even for the verbal list learning (p = 0.007) as for the delayed recall of the words (p = 0.012). Furthermore the buprenorphine maintained persons showed statistically significant the more favourable scores in the working memory performance for figural material (digit symbol test, HAWIE-R) (p = 0.021). Our results indicate a better cognitive performance also after a longer substitution time and results cannot easily be attributed to an "only" transient opioid switching effect. Continued research is still needed to confirm the less impairment on cognitive functions.