Tobacco – Contains nicotine, and harman & norharman which are MAOIs. Smokers have been shown to have 30% lower MAO-A activity and 40% less MAO-B activity than non-smokers.[25] A meta-analysis of 41 double-blind, placebo-controlled studies concluded that nicotine or smoking had significant positive effects on fine motor, alerting attention-accuracy and response time (RT), orienting attention-RT, short-term episodic memory-accuracy, and working memory-RT.[26]
Interesting, eh?