Comment by CamperBob2

One possible case in point, the mathematician's mathematician Paul Erdős, who was said to be a heavy methamphetamine user. From https://en.wikipedia.org/wiki/Paul_Erd%C5%91s :

   After 1971 he also took amphetamines, despite the 
   concern of his friends, one of whom (Ron Graham) bet him 
   $500 that he could not stop taking the drug for a 
   month.[18] Erdős won the bet, but complained that during 
   his abstinence, mathematics had been set back by a 
   month.