Despite advances, a new government survey finds that most kids with autism aren’t diagnosed until age 5, meaning that many are missing out on critical years for early intervention.

The finding comes from a National Institute of Mental Health survey released Thursday of parents and guardians of 1,420 kids with autism ages 6 to 17 who were interviewed in 2011.

More than half of kids with autism in the study were diagnosed after age 5, far later than experts recommend. Currently, the American Academy of Pediatrics advises pediatricians to screen all children for autism at 18 months.

Early identification is important, experts say, as research has found that early intervention can have the greatest success when children begin at young ages.

Once diagnosed, researchers found that most kids were prescribed psychotropic medications including stimulants, anti-anxiety drugs or antidepressants. Those behind the survey say this may be due to co-occurring issues with these children or because of an “absence of clear practice guidelines for psychotropic medication use in children with ASD.”

The majority of children were also using at least one type of therapy to address their needs. Social skills training and speech or language therapy were the most common reported.

Only about 40 percent of kids were receiving behavioral intervention, the report found.