Donepezil in a chronic drug user--a potential treatment?

The objective of the current study was to explore the potential cognitive benefits of an anticholinesterase inhibitor, donepezil, in a former chronic drug user. A neuropsychological test battery composed of the vocabulary and matrix reasoning subtests of the Wechsler adult intelligence scale-III, measures of everyday executive functioning (behavioural assessment of the dysexecutive syndrome [BADS]), and verbal learning and memory tasks (California verbal learning test-II; Rivermead behavioural memory test) was completed at baseline, at 3 months after introducing donepezil, and at 3 months after donepezil was discontinued. After donepezil treatment, substantial improvements were found on tasks of nonverbal fluid reasoning (i.e. matrix reasoning) and other executive functioning tests (i.e. BADS). At entry into the study, poor academic performance and subjective problems with memory and concentration were reported, particularly after amphetamine use (i.e. MDMA and crystal methamphetamine); after donepezil treatment, dramatic increases in memory, concentration and academic achievement were observed. The finding of improvements in tests of executive functioning and in academic performance in this case study, together with the minimal adverse side effects of donepezil, warrants the investigation of controlled studies of cholinergic enhancement in chronic amphetamine and other drug users.