“As a baby, toddler, and preschooler, we always recognized our son was a bit different than other children his age,” Karen Copeland, founder of Champions for Community Mental Wellness, told Healthline. “It was kindergarten or grade one when I started strongly suspecting autism. Our son was diagnosed with ADHD by a pediatrician after a 15-minute interview when he was 6 years old.”

The subsequent experiences of Copeland and her son are an illustration of the study’s findings.

Despite suspecting that her son also had autism around age 6, he didn’t receive the additional diagnosis until age 11.