Maternal depression, antidepressants alter baby language development

Written by Loren Grush

The first few months of a newborn’s life are critical in terms of language acquisition and cognitive development. However, this time period is very sensitive and complex, and various environmental factors can have an impact on a child’s early development.

Now, a new study has revealed that both maternal depression and a common kind of antidepressant are two big environmental issues, which can alter when this learning phase begins in children – ultimately affecting their ability to learn how to speak.

Researcher from the University of British Columbia, Harvard University and the Child & Family Research Institute have revealed that treating maternal depression with a class of antidepressants called serotonin reuptake inhibitors (SRIs) help to speed up the newborn’s ability to grasp and understand the sights and sounds of their native language. Conversely, untreated maternal depression ultimately delayed this period of language acquisition.

According to the scientists, this phase of cognitive development begins before a baby is even born – meaning their prenatal environment is extremely important.

“My work and the work of a lot of other people have shown that we develop in the womb ready to learn any of the world’s languages,” Janet Werker, a professor in the department of psychology at the University of British Columbia and the study’s lead author, told FoxNews.com. “We start out universal listeners, ready to learn what languages we hear and see.”

Werker explained that during this language learning period, newborns are able to differentiate between the characteristics of their native language and the characteristics of languages of foreign speakers. This window of learning eventually closes though, typically around 8 months after birth.

Once the window closes, babies stop paying attention to sounds they do not need and lose the ability to discern between verbal cues that are not utilized in their native language.

“For example, when it comes to the difference between [the words] ‘raw’ and ‘law,’ you as an English speaker can hear that distinction,” Werker said, “but a Japanese adult cannot. However, a Japanese baby can.”

Under most circumstances, the timing of this language attuning phase is tightly controlled by simple maturation, Werker said. In previous research, she analyzed healthy babies who were born up to three months prematurely wondering if whether early exposure to broadcast speech would accelerate the timing of mastering their native language. However, the results showed that the age of conception rather than the age of the baby’s birth dictated when this window of learning opened and closed – meaning the timing is fairly standard for each child.

While the language acquisition phase is seemingly pretty structured, the researchers still wanted to better understand environmental factors they might alter its timing. Werker and her colleagues studied three groups of mothers and their children – who were suffering from maternal depression but not receiving treatment, moms who were taking SRIs to treat their depression, and moms who did not exhibit depression symptoms.

Once the mothers’ babies were born, the researchers examined their eye movements and heart rates when they watched and listened to videos of native and foreign languages – allowing them to determine when language attuning had closed. Each baby was analyzed at three intervals – six and 10 months of age, as well as measuring heart rates of unborn babies responding to languages at 36 weeks in the uterus.

“The results of course showed that exposure to anti-depressant medication in utero, seemed to accelerate this window of opportunity,” Werker said. “If they had been exposed to SRIs in utero, the babies were able to attune to speech differences earlier. Conversely, babies’ mothers who were depressed and were not on SRIs – they started this attuning later.”

Because of previous research showing that this learning period predicts vocabulary acquisition later in life, Werker said that it is important for mothers to be aware of environmental factors such as these that may have effects. However, their study is not meant to tell mothers what to do during pregnancy, she said.

“Depression is complicated,” Werker said. “What we don’t want to do is make depressed mothers feel worse than they already feel. The fact is that pregnancy can cause depression, so we want to help inform so that mothers are making the very best choices they can.”

Given the results, the researchers noted that it is likely that other factors may also accelerate or delay this process – meaning much more research is needed.

“Development is occurring all the time,” Werker said, “and precursors to language development are happening long before babies produce their first word. SRI medication and maternal depression seem to be among that class that change the timing. There are other types of experiences –these are not the only ones that can change that timing. It’s important to study these questions at this very precise level so that we can drill down and specify more precisely exactly what types of environmental experiences will have an impact.”