Young adults with autism, especially those without intellectual disabilities, are at higher risk of depression in young adulthood than those with autism who also have intellectual disabilities. In addition, non-autistic siblings also are at increased risk for depression. These are the findings of an observational Swedish study published online in JAMA Network Open on August 31.
Mental health problems such as depression are common among individuals with autism, but diagnosing them can be challenging. Many people with autism show little facial emotion so how they look may not necessarily match how they feel.
Furthermore, it's unclear whether the increased risk for depression is associated with a family history of the condition, and whether it differs by intellectual disability.
To investigate whether children with autism are more likely to be diagnosed with depression in adulthood compared to the general population, and their siblings, and to determine whether the presence or absence of intellectual disability can influence these risks, a team of researchers analyzed data from 223,842 people from the Stockholm Youth Cohort followed up to age 27.
Between birth and the age of 17, a total of 4,073 participants were diagnosed with autism; about 3,000 had no intellectual disabilities. The researchers used local and national patient registers to obtain clinical diagnosis of autism and depression. Participants were compared with approximately 220,000 age-matched controls without autism, including full and half-siblings.
In children with autism, about 20 percent received a depression diagnosis by age 27, compared to 6 percent of the general population. Depression appeared to be more common in those without an intellectual disability (24 percent) than those with an intellectual disability (9 percent). Additionally, young adults with autism were more than two times as likely to experience depression as their non-autistic full siblings.
However, non-autistic full siblings and half-siblings also had a higher risk for depression—37 percent and 42 percent higher, respectively—compared to the general population. This effect was more pronounced for siblings of children with autism without intellectual disabilities.
Identifying and treating depression in this population may improve quality of life, the researchers wrote. The findings may prompt clinicians to provide relevant resources such as social services, education, and emotional support for autistic patients and their families.
Further research to identify the link between autism and depression may lead to interventions to prevent depression.