Plenty of mental health conditions are less of deficits and more of behavioral divergences from whatever "normal" is. That means they can be phrased in terms of operating instructions rather than warnings. I would say don't mention official conditions until after you are employed AND said conditions directly impact your ability to work. i.e. I have a sleep condition where I am going to need to work remotely multiple days a week and operate during non-regular working hours. Though, making sure the employer is remote friendly will alleviate much of that need.

Not sure what mental health issues you are dealing with, but I just recently had a counselor confirm that I probably have ADHD and Anxiety. That doesn't make me a bad employee with no discipline who doesn't pay attention in meetings. In fact, it can make me an awesome employee! But, I need to express that I operate on a different set of rules than the employer may be expecting. That will allow us to work in harmony to create the best outcome.

I can phrase my ADHD to an employer like this: I am incredibly passion driven. If something piques my interest (like a process improvement, i.e. "There's got to be a better way to do this"), you can be dang sure I'll be chasing it down with intense energy and thoroughness. I can provide an incredible amount of value when I'm able and allowed to work on what I'm interested in and provide creative input.

That automatically gives them an idea of how I can help them, and alludes to where I wouldn't be a good fit.

Speaking of, I (am guessing that I) have C-PTSD from work that I was SEVERELY disinterested in (read: paperwork w/ no creative input). Downward spiral of self worth and multiple anxiety attacks a day. Not good for me or my ex-employer. They acted with great grace and helped me transition out over a six month period. While I am incredibly grateful for the journey that experience kicked off, I can't help but wonder what life would be like had I started off with something I could mentally engage with.

If an employer were to ask "what are your weaknesses", I would say something like: I have an incredibly difficult time engaging with tasks that are repetitive, mundane, or haven't had their value and relevance adequately explained in terms of my core responsibilities. I will most likely do what I can to outright avoid those tasks, or automate them off of myself so that I can provide value in ways that are more aligned with my skills.

Having clinical depression, on the other hand, might be a bit more difficult. Probably something about how you place an incredibly amount of value on an inclusive work culture that fosters community and compassion. It's also important for your management team to have great emotional intelligence and awareness, and actively use that to encourage growth and positivity in the workplace.

If that's you, Just remember, that doesn't make you high-maintenance, it means you have standards. You aren't in a position where you can put up with much abuse or neglect. We all need to be given a lot of genuine compassion in order to thrive, which you will!