Think your sense of morality is ingrained and can't be changed? Think again.
A new study has found evidence that the way we treat others is linked to our brain chemistry - and antidepressants and other drugs can alter this.
Scientists believe that antidepressants could be used to treat antisocial behaviour, after they found that those who took the drug were more likely to act selflessly.
Researchers from University College London (UCL) discovered that antidepressant medication can influence a person's ability to make moral decisions - particularly in terms of whether to act selfishly or selflessly.
A group of 175 adults were asked to administer and receive electric shocks with a financial reward. Those who administered more shocks would reap the benefits financially.
They hoped to gain an understanding of how much pain a person would be willing to inflict on either themselves or someone else in exchange for money.
Half of the group were asked to take citalopram, which is a commonly prescribed antidepressant, and the other half were given levodopa, which is used to treat Parkinson's disease.
Both groups were then compared against a placebo group.
Researchers found that both medications affected decision-making skills in different ways.
Those who had taken a single dosage of citalopram were far more selfless, as they were willing to pay almost twice as much as the placebo group to prevent harm to themselves or others.
Meanwhile, people taking levodopa (the Parkinson's drug) were more selfish and would rather harm others for a financial reward.
According to the Guardian, Molly Crockett, lead author of the research, said: "Our findings have implications for potential lines of treatment for antisocial behaviour, as they help us to understand how serotonin and dopamine affect people’s willingness to harm others for personal gain.
"We have shown that commonly-prescribed psychiatric drugs influence moral decisions in healthy people, raising important ethical questions about the use of such drugs."
The findings were published in the journal Current Biology.
The study echoed research from 2010 where scientists at University of Cambridge discovered that people given serotonin-enhancing drugs were less likely to harm others.