They found a statistical accumulation of dementia diagnoses in those taking anticholinergic drugs compared with those who had not taken this drug. In addition, the more the drug was taken, the more dementia was diagnosed. In the group of patients with the highest total intake who received a high dose of anticholinergic drugs for three or more years daily, the diagnosis of dementia was 49% more frequent than in those who had never had this drug before.
Such a statistical accumulation may point to a causal relationship. However, it may also be a so-called pseudo-correlation without an underlying cause-effect relation. However, if a causal connection would be confirmed in further studies, the researchers say that about 10% of all dementia cases in the UK would be associated with the use of anticholinergics. Patients currently taking anticholinergic drugs should not stop abruptly, but seek advice from their neurologist.
Anticholinergics are prescribed with the aim to inhibit the neurotransmitter acetylcholine in the brain. In the case of patients with Parkinson's symptoms, they are prescribed with the intention to counteract a suspected imbalance between the reduced level of dopamine and its counterpart acetylcholine in the brain.