A single dose of cocaine can interfere with your ability to recognise other people's emotions.

According to new research, the drug can damage social awareness, and can stop users from being able to process negative feelings such as anger, irritation or sadness. So, in other words, the reason you think you're so confident and social when you're high is because you just aren't able to process how annoyed everyone is with you.

“This is the first study to look at the short-term effect of cocaine on emotions,” said Dr Kim Kuypers, the project's lead researcher. “It shows that a single dose of cocaine interferes with a person's ability to recognise negative emotions, such as anger and sadness. This might hinder the ability to interact in social situations, but it may also help explain why cocaine-users report higher levels of sociability when intoxicated – simply because they can't recognise the negative emotions.”

The study, which took place at the Netherland's Maastricht University, started by giving 24 students either 300mg of the drug or a placebo. Each participant was then put through a facial emotion recognition test, and those who had been given the cocaine fared ten per cent worse than their placebo-ed counterparts. They were also found with increased heart rate and significantly higher levels of the stress hormone, cortisol.

The controversial discovery has opened up a larger debate on the long-term effects of cocaine on mental health. “There are many mental illnesses in which our brains' ability to recognise the emotions of others are impaired and this new study shows that cocaine may interfere with this process too,” commented UCL professer Dr Michael Bloomfield after seeing the results. “Since cocaine changes the level of the brain chemical dopamine, this new study may have implications for other mental illnesses such as depression and schizophrenia – where dopamine may also be involved in how we recognise emotions.”

“We know that cocaine is a powerful and addictive drug,” he added. “An important question remains: does cocaine mess up this process so that when cocaine users are off the drug they feel like other people have more negative emotions?”