The drug's active ingredient, acetaminophen, seems to flat-line our emotions, blocking off both the emotional highs and lows, say researchers from Ohio State University. However, people taking the drug don't realise their emotions have been affected.
They made the discovery after they tested acetaminophen on a group of 82 participants, who were given 1000 mg of the drug or a placebo, and then asked their reactions to a series of photographs, ranging from the pleasant to the unpleasant. The acetaminophen group consistently tested less extremely to the images compared to those given the placebo.
(Source: Psychological Science, 2015; doi: 10.1177/0956797615570366)