&gt; It looks like this is just a correlation based on historical availability of Tylenol and related compounds in developed countries.<p>That correlation is drawn, as is a correlation between Alzheimer&#x27;s (and Alzheimer&#x27;s-like symptoms) and symptoms potentially related to a side effect of a prior drug for which PA is the active metabolite, which was replaced by PA in the market.<p>&gt; It&#x27;s not obvious from skimming that the author identifies the cause by which Tylenol allegedly causes Alzheimer&#x27;s,<p>Both the <i>CYTOCHROME P450</i> and <i>PA AND F-AD: EARLY-STAGE CEREBRAL INJURY</i> sections identify particular mechanisms by which PA may cause or contribute to the progression.