Acetaminophen is the main ingredient in the over-the-counter pain reliever Tylenol . Painkillers not only dull physical pain , but they can also dull your emotions . This is according to a new study that claims acetaminophen ( paracetamol ) - the main ingredient in the over-the-counter pain reliever Tylenol and paracetamol - has the ability to weaken feelings of happiness and sadness . Acetaminophen has been in use for more than 70 years , but this is the first time that this side effect has been discovered . Previous research had shown that acetaminophen works not only on physical pain , but also on psychological pain . This study takes those results one step further by showing that it also reduces how much users actually feel positive emotions , said Geoffrey Durso , lead author at the Ohio State University . 'This means that using Tylenol or similar products might have broader consequences than previously thought , ' Durso said . 'Rather than just being a pain reliever , acetaminophen can be seen as an all-purpose emotion reliever . ' Baldwin Way , an assistant professor of psychology at Ohio State University said people in the study who took the pain reliever did n't appear to know they were reacting differently . 'Most people probably are n't aware of how their emotions may be impacted when they take acetaminophen , ' he said . There were two studies of college students . The first involved 82 participants , half of whom took an acute dose of 1000 milligrams of acetaminophen and half who took an identical-looking placebo . They then waited 60 minutes for the drug to take effect . Participants then viewed 40 photographs selected from a database used by researchers around the world to elicit emotional responses . The photographs ranged from the extremely unpleasant , to the neutral and the very pleasant . After viewing each photo , participants were asked to rate how positive or negative the photo was on a scale of -5 ( extremely negative ) to +5 ( extremely positive ) . Results showed that participants who took acetaminophen rated all the photographs less extremely than did those who took the placebo . The researchers do n't know if other pain relievers such as ibuprofen and aspirin have the same effect , although they plan on finding out in future research . They then viewed the same photos again and were asked to rate how much the photo made them feel an emotional reaction . Researchers are not exactly sure how Ty . The researchers do n't know if other pain relievers such as ibuprofen and aspirin have the same effect , although they plan on studying that question . Acetaminophen , unlike many other pain relievers , is not a nonsteroidal anti-inflammatory drug , or NSAID . That means it not thought to control inflammation in the body . Whether that fact has any relevance to possible emotional effects of the drugs is still an open question , the researchers added . In this study , acetaminophen may have tapped into the sensitivity that makes some people react differently to both positive and negative life events . 'There is accumulating evidence that some people are more sensitive to big life events of all kinds , rather than just vulnerable to bad events , ' Durso said . Results showed that participants who took acetaminophen rated all the photographs less extremely than did those who took the placebo . 'People who took acetaminophen did n't feel the same highs or lows as did the people who took placebos , ' Way said . One possibility is that acetaminophen changes how people judge magnitude . Scientists claim acetaminophen may blunt individuals ' broader judgments of everything , not just things having emotional content . The researchers did a second study in which they had 85 people view the same photos and make the same judgments of evaluation and emotional reactions as in the prior study . Participants in this second study also reported how much blue they saw in each photo . Once again , individuals who took acetaminophen had emotional reactions to both negative and positive photographs that were significantly blunted . But judgments of blue colour content were similar regardless of whether the participants took acetaminophen or not . At this point , the researchers do n't know if other pain relievers such as ibuprofen and aspirin have the same effect , although they plan on studying that question . Acetaminophen , unlike many other pain relievers , is not a nonsteroidal anti-inflammatory drug , or NSAID . That means it not thought to control inflammation in the body . Whether that fact has any relevance to possible emotional effects of the drugs is still an open question , the researchers added . In this study , acetaminophen may have tapped into the sensitivity that makes some people react differently to both positive and negative life events . 'There is accumulating evidence that some people are more sensitive to big life events of all kinds , rather than just vulnerable to bad events , ' Durso said .
It looked at acetaminophen ( paracetamol ) , the main ingredient in aspirin . Eighty one people were asked to look at happy , sad and neutral images . Those who took the drug had less extreme emotions towards the photos . People who took pain reliever did n't know they were reacting differently .