Caffeine addicts can literally wake up and smell the coffee

14 May 2019

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Researchers have found that those who can’t go without their morning coffee can sniff out even the tiniest amount in the air.

Many out there can attest to the sluggish feeling experienced when they haven’t had their regular morning coffee, a clear indication of caffeine addition. Now, researchers from the University of Portsmouth have shown that these same people have a heightened ability to sniff out coffee’s aroma compared with non-coffee drinkers.

In a paper published to Experimental and Clinical Psychopharmacology, the researchers documented that not only are habitual coffee drinkers more sensitive to its odour and faster to identify it, but this ability only increased the more they craved it.

“We have known for some time that drug cues – for example, the smell of alcohol – can trigger craving in users, but here we show with a mildly addictive drug that craving might be linked to an increased ability to detect that substance,” said Dr Lorenzo Stafford, an olfactory expert who led the research.

“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.”

Developing new addiction treatments

The research was based on two experiments, the first of which involved 62 men and women divided into those who didn’t drink caffeine, those who drank moderate amounts and those who consumed high amounts.

Each person was blindfolded to test their sense of smell, while trying to differentiate small amounts of coffee odour from odour blanks that have no smell. For the odour recognition test, they were asked to identify as quickly as possible the scent of real coffee and, separately, the essential oil of lavender. This showed serious coffee drinkers could sniff out caffeine faster and in lower amounts than those who didn’t drink it.

“More interestingly, higher craving, specifically that which measured the ability of caffeine to reverse withdrawal symptoms such as fatigue, was related to greater sensitivity in the odour detection test,” Stafford said.

In a second test, 32 different subjects were divided into those who drink coffee and those who do not. They were tested using the same odour detection test for coffee odour and, with a separate test for a control, using a non-food odour. Again, the results showed the caffeine consumers were more sensitive to the coffee odour but, crucially, did not differ in sensitivity to the non-food odour.

This, the researchers said, is the first evidence that caffeine addicts are more sensitive to the smell, potentially opening the doors to new aversion therapy treatments for those addicted to substances with distinctive smells, such as tobacco.

Colm Gorey was a senior journalist with Silicon Republic