“Caffeine is the most widely consumed psychoactive drug and these findings suggest that changes in the ability to detect smells could be a useful index of drug dependency.”
I've been off coffee for around six weeks. It's been a battle. And just yesterday as I walked the streets of Byron, looking at tourists enjoying a sidewalk Mocca, my craving came in with a rush. It seems to me that it isn't just the chemical dependency. If my craving can come in just by seeing coffee drinkers.. isn't that beyond chemistry?
This article expands on the topic, saying habitual coffee drinkers are not just more sensitive to the odour of coffee and separately, faster to identify it, but the more they craved coffee, the better their ability to smell it became.