Paracetamol and ibuprofen can interfere with thoughts and emotions, an ‘alarming’ review suggests.
Over-the-counter painkillers may influence how people process information, react to emotionally evocative images and experience hurt feelings.
This makes them less sensitive in certain scenarios, such as being excluded or even reading about a stranger’s agonising pain, according to scientists.
It suggests the cheap painkillers, which can cost as little as 19p for 12 tablets, block feelings to the brain as well as physical discomfort.
The new review, by the University of California, Santa Barbara, follows warnings over the popular pills and their links to a raised risk of heart attacks, fertility problems and liver damage.
Over-the-counter painkillers may influence how people process information, react to emotionally evocative images and experience hurt feelings
Dr Kyle Ratner, co-author of the study, said: ‘In many ways, the reviewed findings are alarming.
‘Consumers assume that when they take an over-the-counter pain medication, it will relieve their physical symptoms.’
He added that they ‘do not anticipate broader psychological effects’, such as those uncovered in the review of trials.
The review revealed that, compared to those who took placebos, women who took a dose of ibuprofen reported less hurt feelings from emotionally painful experiences.
These included being excluded from a game or writing about a time when they were betrayed.
Men showed the opposite pattern, according to the article published in the journal Policy Insights from the Behavioural and Brain Sciences.
The researchers also found the pills influence the ability to empathise with the pain of others, compared to those taking placebos.
People who took paracetamol were less emotionally distressed while reading about a person experiencing pain and felt less regard for the person.
Researchers in previous studies have also discovered painkillers can alter our ability to process information.
People who took paracetamol made more errors of omission in a game where they were asked, at various times, either to perform or to not perform a task.
The same study also suggested that painkillers can affect reactions to emotional objects.
Those on paracetamol rated pleasant and unpleasant photographs less extremely than those who took placebos.
And other researchers also discovered that the pills can alter discomfort from parting with possessions.
When asked to set a selling price on an object they owned, people on paracetamol set prices that were cheaper than the prices set by people who took placebos.
The researchers also said that while the medicine could have new potential for helping people deal with hurt feelings, more research is needed.
Dr Ratner said it needs to be determined if it would have negative effects for people who take it in combination with other medicines, or who are depressed.
While the researchers emphasised that further studies are necessary before policymakers consider new regulations, they recommend policymakers begin to think about potential public health risks and benefits in case preliminary studies are confirmed.