Medications during conception and pregnancy may be what causes autism

Researchers studied whether antidepressants during prenatal development are what causes autism.

The Archives of General Psychiatry published a study in September 2011, that reveals that mothers who took anti-depressants during the year prior to their child's birth were twice as likely to have a child diagnosed with autism.

Researchers studied 298 mothers of children who had been diagnosed with an autism spectrum disorder (ASD), and 1507 mothers who had children without ASD at the same hospital of the same age and sex. The study was performed using medical records from a Kaiser-Permanente Medical Care Program in California. Mothers were chosen who had full pharmacy access also at Kaiser-Permanente so that filled prescriptions could be correlated with medical information.

What is fascinating about this study, is that Lisa A Croen, and colleagues found that mental health diagnosis in a mother was not correlated with an increased risk of autism, suggesting that maternal mental health disorders (or a presumed genetic predisposition) are not what causes autism. Rather, those women who filled prescriptions for selective serotonin reuptake inhibitors (SSRI's) during the year prior to the child's birth were more likely to have a child diagnosed with an autism spectrum disorder.

The effect was particularly strong for SSRI's taken during the first trimester: a 3-fold increase in risk.

This result is not entirely surprising since previous studies have shown differences in serotonin (an important neurotransmitter) production and signalling in autism disorders. SSRI's can pass the placenta and enter fetal circulation.

It is important to note that the authors suggest that SSRI prescriptions during gestation may account for approximately 3% of autism spectrum disorder cases. So while this is an important finding, it is not the sole cause for the disorders...

especially since autism spectrum disorders include a wide array of symptoms and classifications. In this study, any child who had at least one diagnosis of autism, Asperger syndrome, or pervasive developmental disorder not otherwise specified (PPD) were included. To me, a multitude of classifications and symptoms suggests a variety of causes.

Unfortunately, the sample size was not large enough to subgroup the data into specific diagnoses for the children or the mothers - who could have been diagnosed with depression, bipolar disorder, anxiety, obsessive-compulsive disorder, schizophrenia, or another mental disorder.

Also, this study relied on diagnoses from a variety of doctors, and records of prescription sales. There is no data on whether the patient took the medication, or with what regularity it was taken.

The study found no correlation between the non-SSRI class of antidepressants during pregnancy and risk of autism in the child. Again, the sample size was small, begging additional research. But, it suggests that prospective mothers in need of antidepressants may want to discuss a non-SSRI option with their health care provider.

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