Antidepressants suppress feelings of joy and pleasure—and it could be because they affect our ability to have a sense of reward or success, a new study has found.
Although it’s been known for a while that SSRI (selective serotonin reuptake inhibitor) antidepressants blunt the senses, researchers from Cambridge University have discovered a likely reason: they interfere with our ability to change our behaviour from sensory feedback or enjoy rewards when we are successful.
In the study, people taking the drugs for more than 21 days couldn’t differentiate between one option that almost always delivered a reward and another that rarely did so.
The Cambridge researchers tested the SSRI escitalopram on a group of 66 volunteers who weren’t suffering from depression to see how the drug affected them after 21 days. Their responses were compared to others in the group who were instead given a placebo.
The drugs blunted emotions and pleasurable feelings, the researchers confirmed, and this could be explained by their ability to block any sense of reward from an action, or ‘reinforcement learning’, as the Cambridge researchers describe it.
The participants were asked to select one of two options; one produced a reward four times out of five while the second did so one time out of five. Although those given the placebo quickly learned the difference and started selecting the reward-rich option, those taking the SSRI were unable to differentiate and carried on making their decisions randomly.
“The SSRIs take away enjoyment, and from our study we can now see that this is because people taking them become less sensitive to rewards, which provide important feedback,” said Barbara Sahakian, one of the researchers.
Those taking the drug were also unable to reach orgasm when having sex.