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Antidepressants linked to Autism

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Antidepressants in Pregnancy Linked to Increased Autism Risk.
Antidepressant use during the second or third trimester of pregnancy, particularly use of selective serotonin reuptake inhibitors (SSRIs), nearly doubles the risk of the child's developing autism spectrum disorder (ASD) by age 7 years, new research shows.

The study also showed that maternal history of depression is associated with an increased risk for ASD, albeit the risk is smaller.

"In our multivariate analysis, we found that treatment of depression with antidepressants in the second and/or third trimester of pregnancy was independently associated with an 87% increase risk of having a child with autistic spectrum disorder," Anick Bérard, PhD, of the University of Montreal's Faculty of Pharmacy, in Montreal, Canada, told Medscape Medical News.

"We further found that a history of maternal depression was an independent risk factor for having a child with ASD, increasing the risk by 20%."

The study was published online December 14 in JAMA Pediatrics.

For the study, the investigators evaluated data on 145,456 pregnancies from the Quebec Pregnancy Cohort. They analyzed antidepressant exposure during pregnancy and outcomes in the children from the time of conception to age 10 years.

For the study, a child having ASD was defined as the child's receiving at least one diagnosis of ASD between the time of birth and last date of follow-up; 1054 children (0.7%) were diagnosed with ASD at the mean age of follow-up, which was 6.24 years. Boys with ASD outnumbered girls by a ratio of about 4:1, which the authors note is consistent with rates reported in the general population.

After adjusting for various potential confounders, including sociodemographic and psychiatric covariables, such as maternal age and poverty, the use of any antidepressants in the second and/or third trimester was associated with a significantly increased risk for ASD (adjusted hazard ratio [HR], 1.87; 95% confidence interval [CI], 1.15 - 3.04).

Use of SSRIs in the second and/or third trimester was associated with a higher risk (HR, 2.17; 95% CI, 1.20 - 3.93). The risk was significant after adjusting for maternal history of depression (HR, 2.17; 95% CI, 1.20 - 3.93).

The combined use of drugs from two or more antidepressant drug classes was associated with the highest risk of having a child with ASD (HR, 4.39; 95% CI,1.44 - 13.32).

No increased risk for ASD was observed with the use of antidepressants during the first trimester.

In discussing possible mechanisms, Dr Bérard noted that SSRIs are known to cross the placenta and are found in amniotic fluid.

"The increased risk associated with SSRIs makes sense, because we know serotonin is essential for brain cell development, and we know that SSRIs cross the placental barrier," she explained.