Taking antidepressants during pregnancy increases the chance that the baby will have autism by 87 percent, a new study shows.
Researchers from the University of Montreal reviewed data from over 145,000 pregnancies and concluded the medicines “greatly increase the risk of autism.”
“The variety of causes of autism remain unclear, but studies have shown that both genetics and environment can play a role,” said Anick Bérard. “Our study has established that taking antidepressants during the second or third trimester of pregnancy almost doubles the risk that the child will be diagnosed with autism by age 7, especially if the mother takes selective serotonin reuptake inhibitors, often known by its acronym SSRIs.”
SSRIs are a family of widely prescribed drugs that are believed to work by inhibiting serotonin uptake in the brain. They can help relieve depression.
The findings, published in the journal JAMA Pediatrics, could have profound ramifications as between six and ten percent of pregnant women are being treated with antidepressants.
The researchers were able to control for other causes of autism such as genetic predisposition, socio-economic levels and the age of the mother.
In the study, the researchers found that 1,054, or .72 percent of the children were diagnosed with autism by the average age of 4.5. They also found a large increase in the prevalence of the disease, with 4 in 10,000 having autism in 1966 compared to 100 per 10,000 today.
“We defined exposure to antidepressants as the mother having had one or more prescriptions for antidepressants filled during the second or third trimester of the pregnancy,” said Bérard. “This period was chosen as the infant's critical brain development occurs during this time.
“Amongst all the children in the study, we then identified which children had been diagnosed with a form of autism by looking at hospital records indicating diagnosed childhood autism, atypical autism, Asperger's syndrome, or a pervasive developmental disorder,” she added.”Finally, we looked for a statistical association between the two groups, and found a very significant one: an 87% increased risk.”
The uptick could be explained by better detection of autism in its various forms, and the researchers think “environmental factors” are also contributing to the rise of autism.
“It is biologically plausible that antidepressants are causing autism if used at the time of brain development in the womb, as serotonin is involved in numerous pre- and postnatal developmental processes, including cell division, the migration of neuros, cell differentiation and synaptogenesis – the creation of links between brain cells,” said Bérard. “Some classes of antidepressants work by inhibiting serotonin (SSRIs and some other antidepressant classes), which will have a negative impact on the ability of the brain to fully develop and adapt in-utero”
According to the World Health Organization, depression could become the second leading cause of death by as early as 2020. Antidepressants are likely to be prescribed for some time to come.
Here's a video about the study: