Researchers at the University of California Berkley and UCSF have found that a pill used to treat Parkinson's disease makes people more empathetic. 

Tolcapone prolongs the effects of dopamine, a chemical in the brain associated with reward and motivation in the prefrontal cortex, according to CBS San Francisco. The research team believes the drug makes people more empathetic, less tolerant of inequality and more likely to engage in equitable behaviors. 

The team conducted a double blind study of 35 people. The participants received either tolcapone or a placebo on two separate visits, and then played a game in which they divided money between themselves and a recipient they did not know. Neither the researchers nor the participants knew if they received the placebo or if they received tolcapone.  

The researchers found that those who received tolcapone divided the money fairer than those who had not received the drug. 

Additionally, computational modeling revealed that players became more sensitive to and less tolerant of social inequality when they were under the influence of tolcapone, the Daily Mail reported. Researchers looked at previous studies that showed economic inequality is evaluated in the prefrontal cortex, where they believe prosocial behaviors like equality are evaluated in the brain.  

The scientists hope that this drug could someday help treat mental illnesses like schizophrenia and addiction.

"We have taken an important step toward learning how our aversion to inequality is influenced by our brain chemistry," said Ignacio Saez, the study's first author and a postdoctoral researcher at the Haas School of Business.