“Emotional blunting is a common side effect of SSRI antidepressants. In a way, this may be in part how they work—they take away some of the emotional pain that people who experience depression feel, but, unfortunately, it seems that they also take away some of the enjoyment,” senior study author Barbara Sahakian, Ph.D. from the Department of Psychiatry at the University of Cambridge, said in a statement.
For this study, scientists set out to determine why emotional “blunting” occurs by administering a series of cognition tests and survey questions to 66 volunteers. They found something called reinforcement learning to be substantially lower in those taking SSRIs and involved in the emotional “blunting” phenomenon.
Reinforcement learning refers to the things we learn throughout the day based on rewards. For example, if you go on a walk in the middle of the day and notice your productivity and mood have increased, you learned that a midday walk is a good thing. When that is reinforced over time, you continue to associate that behavior with the subsequent positive feelings.
Based on this study’s findings, it seems that the brain does not register those rewards as strongly with SSRIs, resulting in the emotional “blunting” described by patients.
“From our study, we can now see that this is because they become less sensitive to rewards, which provide important feedback,” said Sahakian.