Mental disorders like depression and anxiety are common, and many people benefit greatly from taking medicines to treat these disorders; this includes women of childbearing age. However, some studies have shown that exposure to antidepressants and other similar drugs in utero may be linked to congenital malformations and neurodevelopmental problems in infants and children. This means that pregnancy can be a time of great concern for women who need medication to treat illnesses: it is difficult to weigh the potential risks to the baby against the benefits of continuing treatment.
The SafeTwoTreat project will advance our knowledge about treatment of mental disorders during pregnancy by introducing a new dimension: the role of genetics. Medications are metabolized in the liver by enzymes, which are eventually flushed from the body. How quickly this happens is partly determined by genetics. People who are fast metabolizers will have the main drug in their bloodstream for less time than slow metabolizers, and this may be linked to the dose of medication received by the developing fetus. By understanding the role of genetics, the SafeTwoTreat study aims to apply personalized medicine approaches to the study of medication safety in pregnant women with mental health problems.
One important aspect of understanding the effect of medications on neurodevelopmental outcomes in children is asking clear questions to inform clinical practice. In a recent commentary in Pediatric Research, I discuss potential problems that come from combining new and long-term antidepressant users under the same category, and how better study designs will allow us to do better research.
Establishing causality is the cornerstone of research that aims to have a meaningful impact on society. However, in studies of medication use during pregnancy, causal effects are difficult to identify. Added to this, the language of causal inference speaks only about average effects in populations, and does not provide information at the individual patient level. Truly robust research must be able to give information about average causal effects, as well as actionable recommendations for individuals who need medical treatment. The SafeTwoTreat study will accomplish both of these ends by using genetic variants related to speed of drug metabolism for two related purposes: exploring the clinical implications of particular genetic markers for maternal and fetal outcomes, with the possibility of applying personalized medicine approaches during pregnancy; and using these genetic variants to carry out Mendelian randomization (MR) analyses, thereby avoiding the pitfalls of bias due to unmeasured confounding that are common to observational studies. The SafeTwoTreat study will compare maternal and fetal outcomes associated with psychotropic medication use during pregnancy, with the goal of identifying women for whom medication use is of particularly high risk, thereby directly informing clinical practice for health care providers who treat pregnant women. Further, causal estimates of the effect of psychotropic medication exposure during pregnancy can inform public health policy decision making.