The drugs—and mainly the SSRI (selective serotonin reuptake inhibitor) antidepressants—lower "the emotional impact of negative events", say researchers from the University of Vienna.
They tested the impact of the drugs on a group of people suffering from acute depression who hadn't taken any antidepressants. They were shown images of people suffering and in pain, while attached to an MRI machine, when they weren't taking an SSRI and again later, after they had taken the drugs for three months.
There was a significant difference between the two sessions; during the drug-free test, their responses were typical and displayed empathy, but after taking an SSRI for three months, their brain activation was different, and parts of the brain associated with empathy weren't responding.
This lack of empathy could lead to abnormal social behaviour, the researchers fear.