A Montreal researcher says the criteria for diagnosing autism has lowered to the point where that diagnosis could become nearly meaningless.

Laurent Mottron says that could happen within five to 10 years.

Mottron and four other researchers analyzed 11 previous major studies carried out since 1966 and found that individuals diagnosed with autism have become progressively less different from the general population.

The analysis found that the differences between the groups have decreased over time in five of the seven main constructs that define autism, including emotion recognition, theory of mind, planning and brain size.

The study's authors say their findings may be due to several factors.

That includes a true increase in the condition, greater public awareness, the fact that a diagnosis leads to greater support, a lowered threshold for diagnosis, the use of "checklist diagnoses" and a greater tendency to diagnose individuals with a normal I-Q.

Mottron says the research points to a rampant problem of overdiagnosis that he blames on schools, doctors and parents.

He says the criteria for a diagnosis have become "trivial," including a child's lack of friends or a dislike of haircuts or tags on clothing.

Mottron says it's "fundamental" for medical professionals to move beyond a simple checklist of symptoms before issuing a diagnosis.