&gt; The western roman empire quite likely degraded in part due to its leadership being brain damaged by lead<p>FWIW, modern historians don&#x27;t believe that. See <a href="https:&#x2F;&#x2F;www.reddit.com&#x2F;r&#x2F;AskHistorians&#x2F;comments&#x2F;23o92d&#x2F;on_cosmos_neil_degrassetyson_said_some_historians&#x2F;cgyxmj3" rel="nofollow">https:&#x2F;&#x2F;www.reddit.com&#x2F;r&#x2F;AskHistorians&#x2F;comments&#x2F;23o92d&#x2F;on_co...</a> for a rundown of the modern scholarship on the question, including a breakdown of Nriagu&#x27;s arguments.