I think most of the the older adults have been diagnosed despite lack of rock solid documentation of early childhood issues because in most cases the records were destroyed decades ago and memories if they exist are personal or family members. In my case a structured interviewed with my younger sister who works professionally with Autistic children was used.
The DSM 5 kind of finesses the issue this way
Quote:
Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life).
I have read accounts of PDD-NOS being used for these situations.
Remember most psychs are NT. They may be more somewhat likely to make a professional conclusion and write a diagnostic report to fit their conclusion then us who would be more inclined go strictly by the criteria.
Is it worth it? Yes for the same explanation, benefit etc reasons those who have solid documentation might find it worth it.
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“Self Acceptance is a process not a performance”
“You are autistic enough. And you always have been”
Professionally Identified and joined WP August 26, 2013
DSM 5: Autism Spectrum Disorder, DSM IV: Aspergers Moderate Severity.