Time The results are the first to suggest a trans-generational contributor to the developmental disorder.
The study, published in the journal JAMA Psychiatry, is the
first to examine the potential legacy that a mother’s experience with
childhood abuse could have on the health of her own children. The
findings are especially sobering given the latest statistics released from the Centers for Disease Control, which found a significantly higher rate of autism spectrum disorders (ASD) — one in 50 compared to one in 88 from a report released in 2012 — among school-aged children than previously thought.
The authors of the JAMA Psychiatry paper studied more than
50,000 women enrolled in the Nurse’s Health Study II, who were asked
about any history of abuse before they were 12. The questions delved
into both physical and emotional abuse, as the women evaluated whether
they had been hit hard enough to leave bruises, as well as whether
adults or caregivers had insulted, screamed or yelled at them. They also
filled out questionnaires about whether their own children were
diagnosed with autism spectrum disorders. The scientists also had access
to the nurses’ health records, so they could adjust for other maternal
health factors known to influence autism risk, including nine
pregnancy-related conditions such as preeclampsia, gestational diabetes, alcohol consumption and smoking.
Women who reported physical, emotional, or sexual abuse when they
were young were more likely to have a child with autism compared to
women who were not abused. The more severely the women were abused, the
higher their chances of having a child with autism; compared to women
who weren’t abused, those who endured the most serious mistreatment were
60% as likely to have an autistic child.[...]
How? The researchers believe that some of the lifestyle circumstances
associated with abuse, such as poor nutrition, could be responsible for
some of the association. It’s also possible that abuse causes
biological changes in a woman’s immune system, including disruption of
the stress response, that
could lead to harmful effects on a developing fetus. Studies have shown
that autistic children showed abnormal stress responses, and it’s
possible that a mother’s altered stress reaction could be passed on to
her child. “Maternal inflammation affects the developing brain, and
maternal inflammation and immune function have been hypothesized to be
causes of autism,” the researchers write.
The researchers also speculate that childhood abuse can leave women
in a state of chronic stress; the constant release of stress-related
hormones could also increase a developing child’s chances of developing
autism, since such androgens have been associated with autistic
symptoms. Finally, a mother’s childhood abuse could be an indicator of a
genetic risk for mental illness, which is often associated with abuse
of youngsters. Studies showed that mental illness and autism may share genetic risk factors, “therefore, the perpetration of child abuse
by grandparents and experience of abuse in childhood by the mother may
be indicators of genetic risk for autism in the child,” the study
authors write.