Psychiatric disorders likely among siblings of those with autism

By Marilynn Larkin

NEW YORK - Various psychological and neurodevelopmental disorders occur more often among siblings of individuals with autism spectrum disorders (ASD), researchers report.

ASD often co-occurs with other disorders, such as intellectual disability, attention-deficit/hyperactivity disorder (ADHD), behavioral disturbances, and anxiety disorders, according to Dr. Alan S. Brown, of the New York State Psychiatric Institute, New York City, and colleagues.

Therefore, the team hypothesized that siblings of individuals with ASD could be vulnerable, genetically or via environmental factors, to "many different types of psychiatric and neurodevelopmental disorders," they write in JAMA Psychiatry, online May 4.

To investigate, they used data from Finnish national registries to compare two groups: 3,578 individuals with ASD and 6,022 of their full siblings and 11,775 controls and their 22,127 siblings.

Overall, a total of 1,319 cases (36.9%) and 2,052 controls (17.4%) had at least one sibling diagnosed with any psychiatric or neurodevelopmental disorder (adjusted relative risk, 2.5).

The largest associations were observed for childhood-onset disorders (29.7% versus 11.6% in controls; aRR, 3.0). These included, among others, learning and coordination disorders (15.7% versus 5.9%; aRR 3.2); ASD (10.5% versus 1.1%; aRR, 11.8); ADHD (5.3% versus 1.5%; aRR, 3.7); conduct and oppositional disorders (5.0% versus 1.9%; aRR, 2.8); and intellectual disability (2.9% versus 1.2%; aRR, 3.1).

In addition, "adult-onset disorders, including schizophrenia and affective disorders, also clustered in siblings of probands with autism spectrum disorders," Dr. Brown told Reuters Health by email.

"The findings suggest that common risk factors and genetic mutations may account for the clustering of these disorders in family members, as well as their comorbidity with autism spectrum disorders among individuals," he said. "This has potentially important implications for clinicians, particularly with regard to identifying siblings at higher risk for these disorders based on a diagnosis of autism spectrum disorder in a proband."

The findings also "offer the potential for improvements in screening and early intervention," Dr. Brown continued. "Further research to be considered includes studying larger numbers of subjects and evaluating the specificity of environmental risk factors for these disorders, as well as informing large-scale genetic studies to search for shared genotypes."

Dr. Eric M. Butter, chief of psychology at Nationwide Children's Hospital in Columbus, Ohio, told Reuters Health by email that given "the large and carefully gathered sample, the researchers' conclusions offer greater generalizability than earlier research on this topic. The science of autism is building and we are getting closer to understanding the mechanisms of the disability. Research like this helps to move us closer to understanding the biology of autism and to the possibility of being able to identify and possibly treat this condition much earlier in development."

"The relationship between autism and other psychiatric conditions in the family also suggests that we may be able to consider more personalized approaches to treatment for autism," Dr. Butter continued. "When we understand what kinds of medical and psychological interventions work for one member of the family with a related but different psychiatric condition, it may be helpful in designing intervention strategies for children with autism."

Dr. Butter added, "This study also reminds us that people with autism may also experience other psychiatric problems such as depression, anxiety, and ADHD. It's possible that families who have children with psychiatric disorders and another child with autism may also be able to identify other conditions such as mood, anxiety, and ADHD in their child with autism."

"The best clinical practice in treating children with autism is to be sure you are treating the whole child," he concluded.

The study was funded by various grants from Finnish foundations and by the U.S. National Institute of Environmental Sciences. The authors made no disclosures.

SOURCE: http://bit.ly/277vsyZ

JAMA Psychiatry 2016.

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