Highly prescribed drugs in Western countries (and even more so since the Covid-19 crisis), antidepressants could make people significantly less sensitive to pleasure, in addition to reducing negative emotions.
Can we still trust serotonin-targeting antidepressants (SSRIs)? While an August 2022 study found they were only effective in a few people – and would do no better than a placebo in 85% of cases – new research published January 23 in the review Neuropsychopharmacology has shown that antidepressants can cause “emotional blunting” in patients, i.e. a decrease in their sensitivity to negative but also positive events. A side effect often reported by patients after taking selective serotonin reuptake inhibitors (SSRIs). “In a way, that may be part of the way they work,” says Professor Barbara Sahakian, lead author of the study. They take away some of the emotional pain that people with depression feel, but unfortunately it seems they also take away some of the fun.”
The researchers recruited a team of 66 healthy volunteers: 32 received escitalopram and the other 34 received a placebo. After taking the treatment for at least 21 days, the participants completed a self-assessment questionnaire and above all underwent a series of cognitive tests assessing learning, inhibition, memory and decision-making.
No impact on cognition
In the majority of tests involving so-called ‘cold’ cognition – either attention or memory, the drug made no difference. No change either on “hot” cognition, that involving our emotions. “The drug does nothing negative on cognition and from that point of view it is very good”reassures Pre Sahakian.
However, less sensitivity to reinforcement learning (the way we learn from feedback given to us about our actions) has been observed. Concretely, the researchers gave the choice between two options, A or B. Choosing A would lead to a reward four times out of five, while choosing B is rewarded only one time out of five. After several rounds, the volunteers learn to understand which is the right choice: after a while, the choices are reversed and the participants then had to learn the new rule. Observation: SSRI patients were on average slower to react to these changes and were less likely to use positive or negative comments to guide their learning. Volunteers taking the antidepressant also reported that they had more difficulty reaching orgasm during sex: another often reported side effect.
Help for hesitant patients
Information that could help patients make more informed choices, but that in no way detracts from the effectiveness of antidepressants. “There is no doubt that antidepressants are beneficial” for many patients, confirmed Barbara Sahakian.
The study reports that 60% of healthy volunteers would have become less sensitive to positive and negative reactions after undergoing the treatment. A number that “could be an overstatement”, according to Catherine Hamer of the University of Oxford, adding that one should not deprive oneself of antidepressants if one needs them. “My concern is that people are seeing this and thinking the message is don’t take drugs. This is exactly the kind of work we need, but it doesn’t affect everyone – everyone is unique and the treatments are still therapeutic”she concluded at the Guardian.