Prenatal exposure to antidepressants and depressed maternal mood alter trajectory of infant speech perception

Abstract

Language acquisition reflects a complex interplay between biology and early experience. Psychotropic medication exposure has been shown to alter neural plasticity and shift sensitive periods in perceptual development. Notably, serotonin reuptake inhibitors (SRIs) are antidepressant agents increasingly prescribed to manage antenatal mood disorders, and depressed maternal mood per se during pregnancy impacts infant behavior, also raising concerns about long-term consequences following such developmental exposure. We studied whether infants' language development is altered by prenatal exposure to SRIs and whether such effects differ from exposure to maternal mood disturbances. Infants from non-SRI-treated mothers with little or no depression (control), depressed but non-SRI-treated (depressed-only), and depressed and treated with an SRI (SRI-exposed) were studied at 36 wk gestation (while still in utero) on a consonant and vowel discrimination task and at 6 and 10 mo of age on a nonnative speech and visual language discrimination task. Whereas the control infants responded as expected (success at 6 mo and failure at 10 mo) the SRI-exposed infants failed to discriminate the language differences at either age and the depressed-only infants succeeded at 10 mo instead of 6 mo. Fetuses at 36 wk gestation in the control condition performed as expected, with a response on vowel but not consonant discrimination, whereas the SRI-exposed fetuses showed accelerated perceptual development by discriminating both vowels and consonants. Thus, prenatal depressed maternal mood and SRI exposure were found to shift developmental milestones bidirectionally on infant speech perception tasks.

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.

Comparison of alternating (Hindi dental and retroflex) trials to nonalternating (Hindi dental) trials after being habituated to Hindi dental syllable (*P < 0.05). Error bars represent SEM. (A) Data from control (n = 25), depressed-only (n = 19), and SRI-exposed infants at 6 mo (n = 27). (B) Data from control (n = 28), depressed-only (n = 16) and SRI-exposed (n = 30) infants at 10 mo.

Fig. 2.

Comparison of final three English habituation trials to two sets of three test trials following the visual language switch to French (*P < 0.05). Error bars represent SEM. (A) Data from control (n = 26), depressed-only (n = 13), and SRI-exposed (n = 23) infants at 6 mo. (B) Data from control (n = 20), depressed-only (n = 16) and SRI-exposed (n = 23) infants at 10 mo.

Fig. 3.

Mean fetal heart rate during a speech discrimination task. The y axis represents fetal heart rate in beats per minute (BPM); the x-axis represents the 10 preswitch and 10 postswitch trials. Preswitch comprises repeated presentations of the same sound, and postswitch comprises repeated presentations of the changed speech sound (*P < 0.05). (A) SRI-exposed (n = 14) and nonexposed (n = 20) fetuses at 36 wk gestation in response to a change in vowel sounds (/a/ vs. /i/). (B) SRI-exposed (n = 14) and nonexposed (n = 20) fetuses at 36 wk gestation in response to a change in consonant sounds (/da/ vs. /ta/).