"From the look of it, he's probably smokin' motherboards..."
In our company there's a tale once they found an employee - working on soldering circuits - who had abnormal lead levels in his blood. They checked all the equipment that should have kept dangers away, and found no issues. Also, the other people working on the same line had not the issue.
Later, after much investigations, turned out he had a little business on his own - and didn't tell anything about it to the company doctors because of course he didn't want the company to know, nor the tax agency - and he was working in a small room without enough ventilation - almost not at all - basically the idiot was poisoning himself, despite being aware of the risks.
So yes, there could be people who smoke motherboards and develop mental issues....