Exposure to Antidepressants in the Womb Makes for Sad, Scared Adolescents

In a new study, researchers found that those exposed to SSRI antidepressants in utero had a hyperactive amygdala and were more fearful and depressed as adolescents. This was true in both mice and humans. Maternal depression did not explain the effect.

“In mice and humans, early-life SSRI exposure alters the offspring’s brain structure and is associated with anxiety and depression-related behaviors beginning in puberty,” the researchers write.

The researchers found that mice exposed to SSRIs in utero had stronger responses to predator odor, and their amygdalae and fear circuits were more activated. Likewise, human adolescents exposed to SSRIs in utero had worse anxiety and depression, and also had hyperactive amygdalae and limbic systems.

The reason the researchers tested both mice and humans was to better assess causality. Research in mice is not confounded by the same factors as study in humans (eg, maternal depression, sociodemographic factors). Thus, since the humans exhibited the same responses as the rodents (e.g., hyperactive amygdalae and fear responses), the researchers conclude that their findings reflect the same causal pathways.

“Mouse to human translation is hardly ever one to one. Yet, parallel translation to humans shows that our findings are clinically relevant and ethologically valid,” they write.

The study was led by Giulia Zanni and Milenna T. van Dijk at Columbia University, New York, and published in Nature Communications.

They write that SSRI exposure in utero “leads to an exacerbated functional response to an innate fear stimulus across neural circuits involved in fear, arousal, and emotional regulation.”