to test their hypothesis, researchers recruited 47 people who suffered from contamination fears (an ocd subtype) and a resulting compulsive cleaning behaviour. participants were given a cup of coffee — some regular strength, some decaf — and then asked to touch a mock “dirty” diaper and wait as long as possible before washing their hands.
“participants in the caffeine group exhibited significantly lower subjective distress and urges to wash their hands both after touching the stimulus and while waiting to engage in the cleansing behaviour,” researchers wrote. “similarly, the caffeine group resisted the urge to compulsively cleanse for about twice as long as those in the no-caffeine group.”
time spent washing their hands (when the caffeine group finally gave in), was similar across both groups, as was subjective distress levels and the urge to wash their hands again later.
“increased arousal due to caffeine intake may increase inhibition, which in turn may play a crucial role in stopping intrusive thoughts (such as disgust), urges and compulsive cleansing in individuals with high contamination fears,” the researchers said.
“patients and clinicians will find it useful to know that it is more feasible to control symptoms during times of high arousal and can use this knowledge to improve treatment outcomes.