[evoloution]

What tanepiper is saying is mostly correct, especially the part that late-onset ADHD is not really a thing. Genetic condition is kind of an inaccurate statement, though, in my experience as a psychiatrist-scientist. You can liberally say that ADHD is ~75% [1] heritable (based on twin studies) which is pretty high. However, data suggest that even though DSM requires a binary definition of the disorder, in truth it is more like a spectrum and less like e.g. bipolar disorder type I which you either have or you don't despite the fact that severity may vary. For example in a recent study, we found that among people, a high polygenic score (PGS; a kind of way to score individuals for genetic liability based on published studies that associate genetic variants with a disorder) is associated with typical deficits in cognitive functions found in ADHD even in the absence of a diagnosis [1]. I conceptualize it as another lever within the natural variation of how brains work and are tuned for different environments.

Now visiting the late-onset part, I have mostly seen it in clinical practice in individuals who had ADHD traits already (may not have met diagnostic criteria) that got really worse after traumatic brain injury and/or worsening of a comorbid mental health conditions e.g. their anxiety or their depression. The natural progression of ADHD for most is to get better over the years as they develop compensatory habits and/or choose lines of work that make ADHD traits less of an obstacle; some believe that also brain maturation kind of catches up at some point which is an incomplete cure. However, the effects on confidence and self-perception are long-lasting...

Another misconception is that high IQ corrects for ADHD traits, this has been mostly rebutted in both clinical literature and we have a genetic study under review that mostly replicates that. Finally, there is an overlap in signs when comparing "bored" gifted individuals and ADHD individuals which can be confusing... Unfortunately, smart individuals with ADHD (of the inattentive type) get enough performance to fly below the radar of diagnosis which ultimately hurts them or delays them from realize "their full potential".

1. https://doi.org/10.1038/s41588-022-01285-8 and for open-access see manuscript at PMC: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10914347/

[tanepiper]

Thank you for a very good answer and you are right, it's not clear cut - as I've got older I identify more AuDHD now, have a relatively higher IQ and if wasn't for my wife (also AuDHD) suggesting we get diagnosed years ago I would have continued the "fly below the radar" - which usually means jumping jobs every two years.

Knowing the diagnosis, with medication, I have much better coping strategies for life now - but at the moment my sink is still full of dishes and there's probably a load of laundry that finished washing 2 days ago still in the machine.