In the case of something like autism, the presentation of symptoms is massively complicated by the amount of support and therapy/'training' a person has had. In

In the case of something like autism, the presentation of symptoms is massively complicated by the amount of support and therapy/'training' a person has had. In a population where everyone had equal levels of Foo and Bar, but a widely varying level of therapy, they would show widely varying levels of 'autism' in their diagnosis - and this would complicate any attempt to study the relationship of Foo+Bar<->autism.