Before anyone considers experimenting with Donepezil or other acetylcholinesterase inhibitors in hopes of enhancing their learning, it should be noted that there are plenty of unknowns and a few serious concerns around altering the cholinesterase levels of otherwise healthy adults.<p>Briefly: Acetylcholinesterase terminates acetylcholine neurotransmission events by deactivating the acetylcholine, allowing it to be reused. An acetylcholinesterase inhibitor such as the Donepezil used in the article inhibits the action of acetylcholinesterase, which in turn enhances acetylcholine neurotransmission in a dose-dependent manner.<p>Highly potent acetylcholinesterase inhibitors are used as poisons (Sarin gas, for example) because they interfere with all of the acetylcholine-based neurotransmission that happens throughout your brain and body. Less potent inhibitors are used at lower doses in Alzheimer's disease as it is hoped that they will improve cognitive function and perhaps even slow disease progression. Thus far the results have been mixed.<p>Now the bad news: Cholinergic neurotransmission is widespread through your brain and your body. Acetylcholinesterase inhibitors are a <i>very</i> blunt and non-specific way to manipulate that neurotransmission. Unfortunately, you can't just enhance memory formation and learning related neurotransmission, you amplifiy cholinergic transmission indiscriminately everywhere. As a result, it's possible to get some quite negative effects as well. There are reports of acetylcholinesterase inhibitors causing or at least inducing PTSD-like symptoms ( <a href="http://www.ncbi.nlm.nih.gov/pubmed/17308243" rel="nofollow">http://www.ncbi.nlm.nih.gov/pubmed/17308243</a> ). Furthermore, we just don't know the long-term effects of these medications on young, healthy adults as they've primarily been studied in elderly populations.<p>In short: It's potentially very unwise to use Donepezil or similar medications for the purposes of enhancing your learning or your memory. Leave the experimentation to the carefully controlled studies until more is known on these powerful substances.