The key facts

  • Of the 109 study participants, half completed a course of interpersonal psychotherapy, while the rest received routine monitoring
  • Infants in the 'therapy' group had a smaller right hippocampus; the left hippocampus and amygdalae showed no differences
  • A causal link has not been proven, and the authors do not yet recommend changing medical practice

What the researchers found

A course of psychotherapy completed by a woman during pregnancy left a trace in her child's brain: infants whose mothers were treated for depression had a smaller right hippocampus than the others. This conclusion was reached by Elizia Poggie Davis and Katherine Demers of the University of Denver and the University of Colorado; the study was published in the journal Nature, as reported by Gazeta.Ru.

How the experiment was conducted

The study involved 109 pregnant women with pronounced symptoms of depression. Of these, 52 completed a course of interpersonal psychotherapy — eight weekly one-hour sessions focused on relationships and social life. The remaining 57 received routine physician monitoring, a lecture on depression, and regular monitoring of their condition. When the children were about six weeks old, they underwent brain MRI scans.

Results and their limitations

The scans showed that infants in the 'therapy' group had a noticeably smaller volume of the right hippocampus — a region important for memory and emotion regulation — than infants in the control group. The left hippocampus and the amygdalae, responsible for processing fear and emotions, did not differ between the groups. The benefit or harm of this difference has not yet been established. One of the authors' hypotheses is that maternal depression accelerates the maturation of the fetal brain, and treatment returns development to its normal pace.

Observation up to six months

Observation of the children up to six months added a detail: the larger the hippocampus, the stronger the negative emotions in behavioral tests. A strong negative reaction in infancy has previously been associated with an increased risk of depression and anxiety in adolescence. This does not prove a causal link: the scan was taken only once, and it is unknown how the differences change with age.

What this means in practice

The mechanism by which therapy affects the fetal brain remains an open question: changes in the mother's symptoms, anxiety, and stress were not associated with the child's brain volume. The results do not call for changing medical practice — choosing psychotherapy for the sake of the child's brain would be premature. 'Depression affects the mother's well-being, birth outcomes, and, as our study suggests, the next generation,' Demers noted. 'Expanding access to treatment during pregnancy could benefit two generations at once.' Earlier, according to the publication, scientists discovered a possible sign of future depression in the child's brain.