Drinking decaf coffee can temporarily reduce the unpleasant symptoms of caffeine withdrawal — even if you know you’re not getting regular coffee. This is the conclusion of a new study by researchers from Australia, who note that an estimated 90 percent of adults drink coffee daily. Symptoms of caffeine withdrawal include headaches, fatigue and irritability. The findings, the team said, could pave the way for new treatments for more serious and harmful drug addictions as well.
The work was led by experimental psychologist Dr Llew Mills of the University of Sydney. He said: “A convincing cup of decaf has the power to reduce withdrawal symptoms a lot when the person drinking it is unaware it’s decaf.
“But our study suggests that even if they are aware it’s decaf, their withdrawal still subsides.”
In their study, Dr Mills and his colleagues recruited 61 heavy coffee drinkers — each of whom habitually consumed at least three cups daily — and had them abstain over a 24-hour period, at the end of which their withdrawal symptoms were monitored.
The subjects were then divided into three groups, two of whom were given decaf to drink, but only one was told it wasn’t regular, caffeinated coffee.
The final group — which served as a control — were given water to drink instead. After three-quarters of an hour, the participants were asked to rate their withdrawal symptoms again.
Dr Mills said: “The group we lied to reported a big drip in caffeine withdrawal even though there’s no pharmacological reason why it should.
“Because they expected their withdrawal to go down, it did go down — In other words, a placebo effect. We’ve found this in several studies now.
“What was interesting in this new study is that withdrawal symptoms also reduced even when people knew they were getting decaf. Not so much as the group we lied to, but a significant amount.”
This type of reaction — when the placebo effect works even when people know they are being given a placebo — is what scientists call an “open-label” placebo effect.
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Prior to being given their experimental beverages, the participants were also asked to rate how much they would expect various drinks to reduce their withdrawal symptoms.
Predictably, the subjects said that they expected the greatest reduction to come from drinking caffeinated coffee. What the team found more surprising, however, was how the participants rated the expected effects of drinking decaf coffee and water.
Dr Mills explained: “Funnily enough, they actually expected water to reduce their withdrawal more than decaf.
“Withdrawal in the group we gave water to didn’t drop at all, whereas the people who were given decaf experienced a significant reduction.
“The reduction they experienced was contrary to what they expected would happen when they were given water and decaf.”
The researchers believe that the open-label placebo effect seen in the study is driven by a strongly conditioned withdrawal-reduction effect.
As Dr Mills explains, the “pleasing increase in alertness and energy” habitual coffee drinkers feel on having their daily cup is, in fact, just caffeine withdrawal being reversed.
Accordingly, after years of associating the smell and taste of coffee with such withdrawal reduction, just drinking decaf can elicit the same response — even without the expectation that it will.
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Dr Mills cautioned that the open-label placebo effect seen in the study is expected to only be short-lived, meaning that decaf coffee won’t reduce feelings of withdrawal indefinitely.
However, he added, “a cup of decaf could help someone who is trying to cut back their caffeine intake to temporarily ride out the worst of the cravings and help them stay caffeine-free.”
Dr Mills concluded: “This study shows cognitive factors like what you expect, and how much of a drug you think you have in your body, have a big effect on how you experience withdrawal symptoms.
“We did this study to model some of the processes involved in addition to any drug, including more serious or harmful drugs,
“What we found has some promise for developing new treatments for addiction that integrate placebo effects.”
The full findings of the study were published in the Journal of Psychopharmacology.