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Missed Autism Diagnoses in Adults and Aged Adults: A Disservice to Multiple Generations

Updated: Jun 7, 2020

Photo by Tim Doerfler on Unsplash

AUTISM AWARENESS: We have grown significantly as an international community in the area of autism awareness. Indeed, it's difficult to find individuals in our culture who aren't "aware" of autism as a large public health issue impacting children and families.

AUTISM RECOGNITION: However, we lag significantly behind in our recognition of autism across all levels of intellect and across the lifespan!! We need teachers who can say "this is what autism looks like in my classroom," individuals to say "this is what autism looks like in my neighborhood," physicians to say "this is what autism looks like in my practice," and adults to say "this is what autism looks like in my undiagnosed parent."


1. Brugha, et al., 2011

The authors of an epidemiological study of autism in 2011 (7,461 adults) concluded:

"The prevalence of ASD in this population is similar to that found in children. The lack of an association with age is consistent with there having been no increase in prevalence and with its causes being temporally constant. Adults with ASD living in the community are socially disadvantaged and tend to be unrecognized."

The authors note that many of the adults identified in the study had not been previously diagnosed on the spectrum. They concluded that adults and geriatric individuals are often unidentified and undiagnosed.

2. Dr. David Mandell, University of Pennsylvania

Dr. Mandell was asked to study the epidemiology of autism in institutions within Pennsylvania. His team developed stringent criteria for diagnosis and found that 10 percent of the residents had undiagnosed autism and the misdiagnosis of a mental health condition, often schizophrenia.

[also, see Baron-Cohen 2009 study and Kim, Young, Shin et al 2011 study y to review rates of children in schools missing correct autism diagnoses]to review their findings about children in schools missing correct diagnoses] . . for information about rates of children missing diagnoses in school]


1. Autism Diagnosis

Did you know that the diagnosis of autism wasn't included in the diagnostic manual until the 1980's? At that time it was a significantly new clinical concept, mistakenly believed to occur largely within intellectual disability and not understood to be neurologic (many felt it was due to poor parenting and "refrigerator mothers"). Because it was such a new diagnosis, many clinicians, teachers, and doctors had no idea what it was or how to look for it (many continue to be ill-equipped in this area today).

2. Incorrect Diagnoses

Many adults and aged adults carry a mistaken mental health diagnosis. Read the article The Missing Generation by Jessica Wright (2015) here.


The diagnostic manual (DSM-5) makes it clear that a diagnosis can be made for adults who were not diagnosed as children.

Although it states the characteristics must be "present in the developmental period," the explanatory material specifies that the recognition of difficulty and the subsequent diagnosis may come later.

Page 53: "The symptoms are present from early childhood... the stage at which functional impairment becomes obvious will vary according to characteristics of the individual and his/her environment."

Page 50 "The symptoms may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life."

Page 56 "Some individuals come for first diagnosis in adulthood, perhaps prompted by a diagnosis of autism in a child in the family or a breakdown of relations at work and home."

The manual notes that a diagnosis should not be withheld simply due to lack of developmental history in an adult or aged adult as long as there is no clear and specific evidence that functioning was neurotypical as a child.

We do a disservice as a community when we allow generations of individuals in the spectrum to continue to be under-served and/or treated for conditions they don't have.

**Note: the clarifying information from the diagnostic manual (as listed above) is included in my intermediate course on autism diagnosis in adults found at

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