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Anticholinergic drugs impair cognitive function by inhibiting the neurotransmitter Acetylcholine (ACh). This reduces the efficiency at which neurons communicate, which is the third driving force behind cognitive function. Common medications with significant anticholinergic properties include antihistamines, antidepressants, muscle relaxants, and many gastrointestinal and cardiovascular medications.

One study followed 13,000 men and women, age 65 or older, for two years. Its conclusions are disturbing. The research found that people taking more than one anticholinergic drug scored lower on a range of cognitive tests compared to people taking none. Even more startling, the death rate for heavy users of anticholinergic drugs was 68% higher.

An article that discusses that study stated that all adjustments were made to try and account for the higher mortality rate.

Dr. Malaz A. Boustani stated, "So far we cannot tell why they are dying, but it wasn't because they were sicker or older." "We adjusted for age, gender, race, other medications they were taking, other diseases, and social status. We adjusted for everything we could, and that signal did not go away."

Dr. Boustani conducted a second study on 4,000 adults living in Indianapolis. The study concluded that those taking three or more anticholinergic drugs for 90 days or more, were nearly three times as likely to receive a diagnosis of mild cognitive impairment when compared to people who did not take any anticholinergic drugs.

If possible, avoid all drugs rated 2 or 3 on the Anticholinergic Cognitive Burden Scale, and keep use of drugs rated 1 to a minumum. If you are taking over-the-counter anticholinergic drugs, discontinue them if possible. If you are taking prescription anticholinergic drugs consult your physician. Some common anticholinergic drugs are antihistamines, Tylenol PM, Advil PM, and Aleve PM.

It gets even worse, ACh is closely linked with synaptic plasticity. If you inhibit the function of ACh, your brain cannot create and strengthen synaptic connections as well. This violates the second driving force. When your brain is less plastic, you have difficulty learning, and creating memories. It should come as no surprise to anyone that these drugs impair cognitive function. Remember, they may increase mortality as well.

I found this research interesting. Call it a coincidence, but many nootropics work the opposite way anticholinergic drugs work. Instead of inhibiting ACh, nootropics increase ACh's functionality. The nootropic chapter will discuss this in more detail.