Lead is definitely used in lots of old paint, but I seem to recall that this one specifically was mercury-based as mercury can induce schizophrenia and hallucinations, whereas lead’s neurological effects are in the “makes you dull and slow” camp.

Also, lead was mostly used in the 1900’s, IIRC. Before that they used even nastier stuff like mercury, arsenic ( I think arsenic in the paint was the cause of death for Napoleon Bonaparte) and chromium.

But then I’m not an MD or a historian; just a chemist trying to recall all of this from bits and pieces I’ve read over the years, so I might be way off base with some of the specifics.