Anxiety in adolescents with autism is a strong predictor of bipolar disorder, depression, and other conditions, according to a large new study conducted by researchers in Sweden. People with autism are known to be at increased risk for other psychiatric conditions, a trend confirmed by a second study in Minnesota. However, the Swedish study found that anxiety predicts conditions like depression and bipolar disorder even without an autism diagnosis.
According to a Spectrum News report this month, researchers in the Swedish study tracked 14,106 identical and non-identical twins. When the children reached age 15, the twins or their parents filled out a mental health questionnaire that included questions about anxiety. While the researchers had expected that a combination of autism and adolescent anxiety would be strongly connected with future psychiatric diagnoses, they were surprised to find that anxiety predicted those conditions even without autism.
Meanwhile, the Minnesota study, led by pediatric neuropsychologist Alexandra Kirsch, found that people with autism were significantly more likely to be diagnosed with bipolar disorder, depression, or anxiety. Kirsch and her team studied 1,014 autistic people born in Minnesota from 1976 to 2000, and 2,028 sex-and-age matched people without autism. 7.3 percent of the autism group was diagnosed as being bipolar by age 30, compared with 0.9% of the non-autistic group.
Professor Diana Schendel, of Denmark’s Aarhus University, said the reasons for the overlap are unclear, though autistic people may be more vulnerable due to struggles maintaining friendships and succeeding in academic and professional roles. Schendel was not involved in either of the new studies.