Autism, antidepressants and pregnancy: Should you be concerned?

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TORONTO — A new study is suggesting that taking antidepressant medications during pregnancy may increase the risk of autism.

This is a good opportunity to review not only the study, but also what we know about autism in general.

Autism is a condition of abnormal brain development, characterized by two issues: problems with communication and/or social interaction and repetitive patterns of behavior.

Depending on how the condition is defined and diagnosed, it can affect up to one or two per cent of the population, and tends to be more common in boys.

It also tends to run in families and the cause is thought to be genetic. On the other hand, we also know that factors in our environment can influence when and how our genes get activated and expressed, so it’s possible that certain exposures during pregnancy or in early life can predispose people to autism.

This brings us to the new study out of Quebec, where scientists tried to determine if the use of antidepressants during pregnancy might increase the risk of autism.

They looked at 145,456 births between 1998 and 2009 and figured out how many of those women took antidepressants during pregnancy, and then looked at how many of those children went on to develop autism.

They found that 1.2 per cent of children who were exposed to antidepressants in the 2nd or 3rd trimester of pregnancy developed autism, compared to 0.72 per cent of children who were not exposed. So the risk was slightly higher.

But the study comes with lots of caveats.

They used registry data to determine autism diagnoses, and this type of information is not completely accurate.

Previous studies have suggested that depression alone in the mother can increase the chance of autism in the child, which makes it challenging to figure out if the increased risk was caused by the medications, or by the depression itself (authors did try to address this, but the study design made it impossible to eliminate this possibility completely).

A much larger Danish study from 2013 looked at over 600,000 births, and found no such association.

Even if there is an association, we have to keep in mind that 99 per cent of children born to mothers who were taking antidepressants in this study did not develop autism.

On the other hand, untreated depression in pregnancy has major consequences for babies, so we cannot make a blanket recommendation to avoid antidepressants during pregnancy.

People have also heard the myth that autism is caused by vaccines.

This is based on a single fraudulent study published in 1998, but since then we’ve had multiple large studies covering over one million children that show that the risk of developing autism is the same in children who do and do not receive vaccines.

Most recently, a study has shown that even in children with siblings who have autism, vaccination does not increase the risk of autism.

There’s a wider conversation going on about what autism really is.

A fascinating book called “Neurotribes” published this year, traces the history of autism, and points out that many children with autism in fact possess extremely unique artistic and intellectual gifts, and go on to do amazing things.

The reality is that autism truly is a spectrum of conditions, and there’s lots we have yet to learn about it.