Neuropsychological functioning of opiate-dependent patients: a nonrandomized comparison of patients preferring either buprenorphine or methadone maintenance treatment.

OBJECTIVES: In the present study, we investigated whether buprenorphine as a partial mu-opioid receptor agonist is associated with less cognitive impairment than methadone.

METHODS: Neuropsychological functioning of opioid-dependent patients, previously assigned to methadone (MMP, n = 30) or buprenorphine (BMP, n = 26) maintenance treatment according to their own preference, was compared and dose effects were investigated.

RESULTS: MMP and BMP performed equally well on all measures of neuropsychological functioning including the trail making test, the continuous performance test, and a vigilance task. However, patients receiving a higher dose of methadone were impaired in a vigilance task.

CONCLUSIONS: In a free-choice administration of methadone or buprenorphine, there seems to be no difference in cognitive functioning. Possible explanations are discussed.