Women with depression in pregnancy or a history of depression have decreased quality of mentalization in the speech to their infants.

Background: Our study aims to understand whether depression, either in pregnancy or lifetime, affects cognitive biases (comprising the attentional focus and affective state) and mentalizing features (ability to understand children's internal mental states, thereby detecting and comprehending their behavior and intention), in maternal speech during mother-infant interaction in the first postnatal year.

Methods: We recruited 115 pregnant women (44 healthy, 46 with major depressive disorder [MDD] in pregnancy, and 25 with a history of MDD but healthy pregnancy) at 25 weeks' gestation. Three-minute videos were recorded at 8 weeks and 12 months postnatally for each dyad. Maternal speech was transcribed verbatim and coded for cognitive biases and mentalizing comments using the Parental Cognitive Attributions and Mentalization Scale (PCAMs).

Results: Women suffering from antenatal depression showed a decreased proportion of mentalizing comments compared with healthy women, at both 8 weeks (0.03 ± 0.01 vs. 0.07 ± 0.01, P = 0.002) and 12 months (0.02 ± 0.01 vs. 0.04 ± 0.01, P = 0.043). Moreover, compared with healthy women, both those with antenatal depression and those with a history of depression showed decreased positive affection in speech (0.13 ± 0.01 vs. 0.07 ± 0.01 and 0.08 ± 0.02, respectively P = 0.003 and P = 0.043), and made significantly fewer comments focused on their infants' experience at 8 weeks (0.67 ± 0.03 vs. 0.53 ± 0.04 and 0.49 ± 0.05, respectively P = 0.015 and P = 0.005). In linear regression models women's socioeconomic difficulties and anxiety in pregnancy contribute to these associations, while postnatal depression did not.

Conclusions: Both antenatal depression and a lifetime history of depression are associated with a decreased quality of women's speech to their infants, as shown by less focus on their infant's experience, decreased positive affection, and less able to mentalize. Examining maternal speech to their infants in the early postnatal months may be particularly relevant to identify women who could benefit from strategies addressing these aspects of the interactive behavior and thus improve infant outcome in the context of depression.