Medication, which Americans favor over other forms of therapy, poses risks to a developing fetus, but so does having a depressed mother
There's no denying that we pass diseases down from one generation to the next, thanks to our genes and/or the climate in which we raise our children. The classic example is overweight parents with overweight kids. They have inherited a gene linked to obesity or picked up poor eating habits, or both. But this phenomenon doesn't just apply to physical diseases and disorders. Oh no. We also pass our mental health issues down to our kids, from little personality quirks to more serious problems, like worry, anxiety, obsessions, compulsions, and depression.
Depression is a prime example of a disorder that runs through both genes and the environment. When a woman is pregnant, the chemical environment in her body and brain has an effect on her fetus' development. And when this "climate" is off, as in the case of depression, it seems to lead to a specific set of psychological and physiological risks to the child -- from premature birth to emotional and social problems -- that are distinct from those associated with mental health issues in other periods of maternal life. And new research is asking whether, when it comes to the child's health, it's better to treat depression during pregnancy or just leave it alone.
Antidepressants, which Americans are increasingly favoring over other forms of therapy, come with a significant set of risks to the developing fetus, which are expressed in both the brain and behavior of the offspring. A recent study found that one of the most widely used classes of antidepressants, selective serotonin uptake inhibitors (SSRIs), given to rats in the perinatal period -- just before and after birth -- had a significant effect on brain development. This "critical period" in rodents is thought to correspond to the third trimester in humans.
The fetal and neonatal rats exposed to SSRIs showed altered electrical activity in the brain, and reductions in a major serotonin circuit, the raphe system. They also had deformations in the corpus callosum, the bundle of fibers that allows the transfer of information between the two hemispheres of the brain: specifically, there were deficiencies in the cells' insulation, the myelin sheath, which swathes nerve fibers to speed communication. Physiological changes are usually expressed in behavioral changes, and this was true here, too: The animals given SSRIs showed a reluctance to explore new environments and an exaggerated fear response to a novel sound. These alterations in rodent behavior are thought, significantly, to mirror autism in humans.
This SSRI-autism connection is not new, and it's not distinct to rodents. In fact, a study earlier in the year suggested that using antidepressants during pregnancy is linked to a greater risk of autism in human children. The mothers of children on the autism spectrum were three times as likely to have been on antidepressants during the first trimester of pregnancy. While this doesn't nail down cause-and-effect, the researchers controlled for enough variables -- like maternal age and education, sex of the child, birth weight, and how complicated the birth -- that the link seems likely, particularly in light of the new study.
Of course, there are other ways to treat depression in pregnant women. But another new study, or at least in one interpretation of it, raises the possibility that not treating depression in a mother may be the best option for her fetus. In the study, mothers-to-be, whether or not they were depressed before giving birth, had kids that progressed through the developmental stages normally if they stayed with the mental state with which they started. That is, it was actually better for the baby if his or her mother's depression stayed consistent between pregnancy and giving birth than if it lifted. But women who went from happy to depressed or depressed to happy after giving birth had kids with slowed development.
Despite their findings, the authors of this study say that it is better to treat depression in pregnant women, since leaving it untreated can lead to a host of problems for their children later on. Though consistency in the move from prenatal to postnatal environments is a possible explanation for their findings, it's suspect, since it seems intuitive that improved maternal mood should benefit the child. Perhaps the real issue here is how we choose to treat depression. Therapies that use different means to alter the brain (like talk therapy or cognitive behavior therapy) can be as effective as antidepressants, and would not likely pose much risk to the fetus.
Mood disorders, possibly during pregnancy and certainly after a child is born, are somewhat unique in the sense that not treating them in a parent can increase the child's risk for developing them. This is not strictly true for other medical issues, like arthritis or high blood pressure. For example, the mother of an eight-year-old child who treats her hypertension with medication does not reduce her child's risk of developing it, but, because of the additional environmental factor, she would decrease her child's risk for depression if she treated her own. That said, leaving medical conditions untreated in pregnancy is generally not good for the fetus, though the list of medications that can affect the development of the fetus when used during pregnancy is long. Deciding whether it is better to pass on a disorder or the side effects of the treatment to our kids is a decision many of us must make.
Image: Piotr Marcinski/Shutterstock.