Also worth pointing out that ADHD is one of the most well understood diorders out there, and one of the most easily testable and medicated.

I can't count how many people I know or have heard from who have struggled with "motivation" all their lives, and then they took one ritalin one day and, instead of getting hyper and bouncing off the walls like their friends do, they were suddenly able to just sit down and focus on something in a way they'd never experienced before, without any of the struggles that they've suffered their whole lives, and been blamed for by the ignorant parent poster above.

And yeah, you don't have to medicate; it's definitely not for everyone, and I know someone personally who very clearly has ADHD (and a diagnosis) but cannot tolerate any of the available medications. Instead, she just has to find a way to work her life such that the downsides of ADHD don't affect her as much and she can lean on the benefits of ADHD to get through it. Still, just hearing "you're not a fuck-up, it's just how your brain works" can be extremely healing.