Are there links between Alzheimer’s disease and ADHD? The efficacy of acetylcholinesterase inhibitors and NMDA receptor antagonists in controlling ADHD symptoms: a systematic review

To assess the effectiveness, safety, and tolerability of anti-Alzheimer agents (memantine, galantamine, rivastigmine, and donepezil) in controlling ADHD symptoms in children, adolescents, and adults. Following the PRISMA guideline, clinical trials assessing the potency of anti-Alzheimer medications in managing ADHD symptoms were imported from PubMed, Web of Science, and Scopus (until February 2023). Screening stages were conducted by two independent researchers. Two independent researchers also extracted data from clinical trials reporting the outcomes as the reduction in scores of ADHD questionnaires. The risk of bias within the included studies was assessed using the Cochrane Collaboration tool, while the certainty of outcomes was evaluated based on the GRADE criteria. Of the initial 1597 studies, 11 studies were included. No studies were available for rivastigmine, and only a single study was conducted for galantamine. The results of the other two medications had a slight inconsistency. While both memantine and donepezil were reported to be effective in several studies, they were reported to be ineffective in some other studies. Side effects were mostly reduced appetite and headache. The tolerability of memantine, donepezil, and galantamine was all convincing. While galantamine did not demonstrate a promising efficacy in ADHD, memantine and donepezil showed effectiveness. However, future studies are needed to confirm their efficacy in ADHD since there was some inconsistency.