[Raises hand]
In terms of getting to FIRE, the hardest part for me is just keeping my job and the income to save. Thankfully my anxiety generally wins out over my depression, which makes me perform at work even though I'm suffering through it.
When it comes to saving, I think anxiety and depression are perversely advantageous. My anxiety causes me to worry about financial stability more than I reasonably should, which keeps me from committing to fancy purchases. My depression makes me not want to do anything and since doing things costs money, that's also an unfortunate win.
And I don't judge myself too harshly for caving in on small purchases. If your mental health problems cause you to go out and buy a McMansion and a Ferrari, then yea that's a problem. But if you succumb to depression laziness and $60 Postmates occasionally, it's not going to throw you completely off the rails for FIRE.
I sometimes worry that my pursuit of FIRE is motivated by the wrong reason, work-related anxiety. Part of me wonders if taking a year sabbatical now could really improve my mental health. But I'm not willing to walk away from my current deal to test that hypothesis, so I'm still on the path to FI. If I RE and figure out it's not for me, then I'll go back to work. The point is you don't need to be absolutely certain that FIRE is the right path as long as pursuing it doesn't cause any irreversible harm. Worst case scenario, you keep working until traditional retirement age and become filthy rich.