People on antidepressant medication tend to also report experiencing diminished emotional awareness, a condition known as alexithymia, according to a preliminary study published in the journal Experimental and Clinical Psychopharmacology.

“In my experience, up to 10-20% of clinical patients who are prescribed serotonergic antidepressants experience emotional side-effects (apathy, emotional blunting, reduced positive feelings, reduced empathy etc.),” said study author Jani Kajanoja of the University of Turku.

“We noticed that this area has been researched very little, so psychiatrists don’t know whether it’s an actual side-effect of drugs, and what would be the possible mechanisms.”

The researchers compared 57 individuals on antidepressant medications to a control group of 441 individuals not on antidepressants. The specific drugs being used in the study were fluoxetine, sertraline, escitalopram, venlafaxine, paroxetine, citalopram, amitriptyline, clomipramine and mirtazapine.

Compared to the controls, those on antidepressants were more likely to report having difficulty identifying their feelings.

“We found that individuals using serotonergic antidepressants had more subjective difficulty identifying their feelings, compared to matched controls,” Kajanoja told PsyPost.

Those on antidepressants were more likely to agree with statements such as “When I am upset, I don’t know if I am sad, frightened, or angry” and “I don’t know what’s going on inside me.”

But antidepressants are not necessarily to blame.

“Our study was cross-sectional, so it still doesn’t prove that this is an actual side-effect of the drugs. There are other possible explanations, such as antidepressants being more easily prescribed to individuals with lower emotional awareness,” Kajanoja explained.

“The strength of this study was that we did not explicitly ask about antidepressant side-effects, therefore the results are not likely to be affected by response bias.”

“Our results do highlight that more research is needed to clarify how antidepressant use affects emotional awareness and emotional processing.”

The study, “Is Antidepressant Use Associated With Difficulty Identifying Feelings? A Brief Report“, was authored by Jani Kajanoja, Noora M. Scheinin, Max Karukivi, Linnea Karlsson, and Hasse Karlsson.