A community survey in England identified people with autism or asperger's syndrome  and found none of them knew they have it.    And autism turned out to be more prevalent in males with lower education and in government housing.

Is autism causing people to have lower education and jobs or has the umbrella gotten so large it has become a blanket diagnosis for everyone not successful?

The results from the first ever general population survey of autism in adulthood. They are based on a two phase epidemiological survey in England (7,461 screening interviews; 618 diagnostic) carried out in 2007. The findings are in the Archives of General Psychiatry.

If accurate and a lot of people with autism have never been diagnosed with autism,  Dr. Traolach Brugha, Professor of Psychiatry at the University of Leicester and consultant psychiatrist with the Leicestershire Partnership NHS Trust, said that confirms claims from another survey (2009) stating that 9.8 out of 1,000 adults in England meet official diagnostic criteria for autism spectrum disorder -  no evidence of an 'autism epidemic', in adults anyway.

Brugha said, "Overall our findings suggest that prevalence is neither rising nor falling significantly over time. This favours the interpretation that methods of ascertainment (case finding) have changed in more recent surveys of children compared to the earliest surveys in which the rates reported were considerably lower."

In a comment on the possible causes of autism the researchers suggest that "the [non genetic or environmental] causes of autism appear to be temporally constant, and that recent apparent rises in rates of diagnosis must therefore reflect better case finding, rather than some new environmental toxin. However, we would urge caution and the need for independent replication of this first set of adult community survey findings".

Brugha also drew attention to the newly reported finding that none of their cases of autism were already known to have the condition: "It is very concerning that none of the cases we confirmed using rigorous diagnostic assessment methods in the community knew that they had the condition or had an official diagnosis. As in all community surveys it is of course likely that most of the cases we found were relatively mild and few were severe. We know that severe autism particularly when accompanied by learning disability is much more likely to be recognised. We are beginning to provide training to psychiatrists in the diagnosis of autism spectrum conditions in adulthood through the Royal College of Psychiatrists Education and Training Centre, London."

The initial findings of the survey, which appeared first in 2009 attracted considerable media attention. The survey was carried out jointly with the National Centre for Social Research (www.natcen.ac.uk) and a team of methodological experts from collaborating Universities (University of Cambridge, UCL, and King's College, London). Further work extending the survey to adults in communal establishments and adults with Learning Disability has since been commissioned by the NHS Information for the Department of Health and is being carried out in collaboration with researchers at the Universities of Cambridge and Glasgow. The findings are expected to become available later in 2011.