Autism and Antidepressant Use During Pregnancy
As Autism Awareness Month winds to a close, I thought I’d mention another study released this month about a possible risk factor for autism. Conducted in Sweden, the study’s authors examined data from a national database that included nearly 50,000 patients. They looked for patterns regarding antidepressant medication use by pregnant women and later diagnoses of autism among their offspring.
The investigators concluded that use of antidepressants—including modern selective serotonin reuptake inhibitors (SSRIs), such as Prozac®, or Zoloft®, and older tricyclic antidepressants, such as Elavil® or Tofranil®—may account for less than 1% of autism cases. In particular, researchers noted, these were cases of autism “without intellectual disability”. Investigators were careful to point out that this type of study, called a “nested case-control” study, cannot draw firm conclusions regarding causation. That is to say, while a statistically significant number of patients with autism were born to mothers who took antidepressant medications during pregnancy—which suggests antidepressant use may cause an increased risk of autism—it’s also possible depression itself has some impact on the risk of autism, rather than medication use.
Even if this study has identified a genuine causal link between antidepressant use during pregnancy and the risk of having a child with autism, “antidepressant use during pregnancy is unlikely to have contributed significantly towards the dramatic increase in observed prevalence of autism spectrum disorders,” investigators wrote, “as it explained less than 1% of cases.” Interestingly, an earlier case-control study, performed in California, reached a similar conclusion. The authors of that study found that exposure to antidepressant medications in the womb, especially during the first trimester of pregnancy, was associated with a modest increase in the risk of autism spectrum disorder.
Croen LA, Grether JK, Yoshida CK, Odouli R, Hendrick V. Antidepressant use during pregnancy and childhood autism spectrum disorders. Arch Gen Psychiatry. 2011 Nov;68(11):1104-12. doi: 10.1001/archgenpsychiatry.2011.73. Epub 2011 Jul 4.
Rai D, Lee BK, et al. Parental depression, maternal antidepressant use during pregnancy, and risk of autism. Autism spectrum disorders: population based case-control study. BMJ 2013;346:f2059