What does undiagnosed ADHD look like in adults?

My therapist said the following:

“Often, when a person with ADHD remains undiagnosed into adulthood, they will one day become depressed due to their dopamine deficiency. So they go to the doctor, and no one, not even the doctor knows that the patient has ADHD. Then, the patient goes to the psychiatrist and various antidepressands are tried, but none of them works. It’s because patients with ADHD need different antidepressands than people without ADHD. So now we have a severely depressed adult, who can’t seem to get any antidepressand to work on them. Therapies don’t work either, as people with ADHD need different therapies than people without ADHD. The best course of action would be to test that person for ADHD, but the sad reality is, no one thinks of it, as the patient doesn’t even notice how they mask their hyperactivity, and that their restlessness simply turned into inner turmoil. There are a lot of undiagnosed ADHD patients out there, who are simply labelled as having untreatable depression.”

That therapist has a specialization in ADHD btw. It’s usually psychiatrists and psychologists who aren’t specialized in ADHD who don’t think of stopping and testing the patient for ADHD, “just in case”. That’s also what several psychologists at the clinic said.

Source: quora.com by Living with Adult ADHD