Behavioral conditions such as attention deficit hyperactivity disorder (ADHD) crop up in about one in three autistic people within 15 years of their autism diagnosis. About 20 percent of autistic people are diagnosed with anxiety in that time period.
A study of nearly 6 million people reveals the onset and prevalence of nine such diagnoses that often accompany autism.
Most of the findings fit with prior research. For example, the ADHD finding jibes with several smaller studies reporting that roughly one in three people with autism has ADHD. But the new analysis draws on an unprecedented amount of data.
Roughly 20 percent of autistic people received a diagnosis of a neurotic condition, such as anxiety — previous studies have estimated anywhere from 11 to 84 percent. The estimate from this study is on the low end because some clinicians may consider anxiety a part of autism and therefore don’t diagnose it separately.
The study also breaks fresh ground for a group that gets little research attention: middle-aged autistic adults. More than 10 percent of people diagnosed with autism from age 40 to 60 develop a dementia condition such as Alzheimer’s disease within 15 years.
Read full, original post: Autism diagnosis often followed by identification of other conditions