Clinical research: Maternal depression linked to mild autism
Women who have a history of bipolar disorder or depression are more likely to have a child with Asperger syndrome than classic autism, according to a study published in the 2012 issue of Autism Research and Treatment. The study makes use of crowd-sourced data collected in an online database1.
This suggests that the genetic risk factors for Asperger syndrome overlap with those involved in depression, the researchers say.
Another study, published 22 August in the Journal of Child Psychology and Psychiatry, shows that children with autism whose mothers have mood disorders tend to have emotional problems themselves.
Parents of children with autism often have some symptoms of the disorder without meriting a full diagnosis — a phenomenon called the broad autism phenotype (BAP). BAP often includes depression, although the symptoms of depression may also result from the stress of caring for a special-needs child.
Children diagnosed with Asperger syndrome have good language skills and cognitive abilities. The syndrome is often thought to be indistinguishable from high-functioning autism.
The first new study uses data collected from the Interactive Autism Network to parse the connection between maternal depression and autism. The researchers analyzed data from 998 women who have a child with autism or Asperger syndrome and who filled out the Maternal Mood Disorders questionnaire.
They compared mothers who have an official diagnosis of depression or bipolar disorder with those who reported that they have never suffered from mood disorders. They excluded women who said they have depression, but do not have a clinical diagnosis.
Women diagnosed with bipolar disorder are roughly twice as likely, and women diagnosed with depression 1.6 times as likely, as controls to have a child with Asperger syndrome, the study found.
Of the 487 women with mood disorders, 329 said they've had symptoms their whole lives. These women are about 2.4 times more likely than the 158 who only had symptoms after pregnancy to have a child with Asperger syndrome. This suggests that the association between maternal depression and Asperger syndrome is the result of a long-term, potentially genetic, condition.
The second study looked at 16-year-olds who had been assessed at 12 years of age as part of the Special Needs and Autism Project. This initiative, launched in 2006, sought to identify undiagnosed individuals with autism among nearly 57,000 children in the South Thames region of London.
The researchers used two parent questionnaires — the Profile of Neuropsychiatric Symptoms and the Strengths and Difficulties Questionnaire — to diagnose severe mood problems, such as extremely strong reactions to negative experiences, in 79 children with autism.
The 24 children with mood problems tend to have mothers who also have mood problems, the study found. They are also more likely than children without mood problems to have trouble recognizing a surprised facial expression.
The study is one of the first to document mood disorders in children with autism, the researchers say.
1: Vasa R.A. et al. Autism Res. Treat. 2012, 435646 (2012) PubMed
2: Simonoff E. et al. J. Child Psychol. Pyschiatry Epub ahead of print (2012) PubMed
3: Baird G. et al Lancet 368, 201-215 (2006) PubMed