One of the reasons people turn to supplements is that drugs often have side-effects which make their use, especially over the long term, more damaging than helpful. That may be the case with long-term use of some common over-the-counter drugs to aid sleep.
A 2010 study published in the journal Neurology, for example, looked at drugs called anticholinergics, which block acetylcholine, a nervous system neurotransmitter. They include such common over-the-counter brands as Benadryl, Dramamine, Excedrin PM, Nytol, Sominex, Tylenol PM, and Unisom. They are taken for a variety of common medical conditions including insomnia or allergies. Unfortunately, according to this Indiana University study, over the long term these drugs also produce cognitive impairment. According to the study authors, taking “one anticholinergic significantly increased an individual’s risk of developing mild cognitive impairment and taking two of these drugs doubled this risk.”
Given these risks, it makes sense to consider such alternatives as Melatonin or 5-HTP. While these supplements, like many others, should be taken carefully and according to recommendations, we don’t know of any research suggesting that they produce cognitive impairment over the long run!