Why It Happens When someone receives a late diagnosis of ADHD or autism, it can feel like an emotional earthquake—unearthing years of struggle, misunderstanding, and missed support. For the individual, this is often a period of profound re-evaluation. And for those around them—especially their manager—it can be a period of sudden and surprising relational change.

You’re managing someone you’ve worked with for months—maybe years. The relationship has had its ups and downs, but overall, it’s been solid. And then something changes. They get a diagnosis: ADHD. Autism. Possibly both. What follows can feel confusing, unsettling, even a little hurtful.

Why do some people seem to lose ability after diagnosis of autism or ADHD? Is it skill regression, or is it something else?