Reconsidering the Age-of-Onset Criterion in Older Adults Being Evaluated for ADHD

The current Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) requires evidence of symptom onset before age 12 to make a diagnosis of ADHD in adults.

A recently published clinical review questions the appropriateness of this criterion in older adults 50 years old and above. It sets forth several reasons:

·        ADHD was first recognized in the DSM in 1968, just over fifty years ago. Anyone over fifty is highly unlikely to have been diagnosed with ADHD in childhood, or even to have symptoms properly noticed.

·        It is well-established that memories both fade and change with time. Even among young adults, only about half can recall the age at which specific memories occurred. For older adults, the challenge is much greater, and that means questionnaire answers become unreliable.

·        Episodic memory among persons with ADHD is known to be impaired relative to controls, which further limits the reliability of memory, especially over extended periods.

On the other hand, the reason for the early onset criterion is to avoid any confusion with early neurodegenerative diseases such as Alzheimer’s or Lewy body dementia, which have overlapping symptoms.

The authors suggest a possible fix:

·        For those over fifty, readjust the under-12 criterion to instead demonstrate the longstanding previous existence of ADHD symptoms, without forcing it to include the first eleven years of life. They call for research to determine how many years of previous symptoms would best distinguish ADHD symptoms from normal aging and the onset of dementia.

·        Establish a family history of ADHD. Heritability estimates suggest that ADHD occurs in roughly half the parents of people with ADHD, and about 15% of grandparents. That means that for persons over 50, having children and/or grandchildren with ADHD would lend greater weight to self-reported ADHD symptoms.

·        Noting that “cognitive functioning rating scales(e.g., the Barkley Deficits in Executive Functioning Scale) have shown to align robustly with ADHD symptoms,” they “call for studies investigating the use of these rating scales in older adult samples, and particularly their discriminant validity relative to other late-life disorders affecting cognition.”

·        This would be accompanied by careful screening for physical or psychiatric comorbidities, to reduce the risk of false positives.

It is unethical, the authors suggest, to deny care to older, presently undiagnosed adults, given the demonstrated poor outcomes associated with untreated ADHD.

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