I'm a OL but I did just want to put my two cents in here. I've worked for years in a psychology practice, with many of our clients being lawyers. Their clinical presentation can range from mild to severe mental illness that they are currently managing but come in to therapy for continued support. Otherwise they are leading perfectly fulfilling lives and careers. I don't think there needs to be such a stark dichotomy between those with diagnoses and those without. It is not a sentence and it doesn't define you. It's an additional burden, for sure. But I don't believe people with diagnoses need to be seen as being so fragile under pressure - usually it's the contrary, often they've had years of living with mental illness that has enabled them to build resilience as well as coping mechanisms for dealing with stress. I don't mean to say law is the ideal choice for someone with an active disorder but for someone who has experienced these issues in the past and managed to overcome it, it could even be seen as an asset.
I would say prepare yourself with the tools that have helped you in the past and ensure you have a solid support system. Hope this helps and best of luck with everything!