If you had to create a mental health checklist, kinda like a car scheduled check at 25, 50, 100k miles etc. You have 3 options:
1. Go down a list of DSM descriptions of likely pathologies and ask for each, "do I have that? do I need to fix that"
2. Do some sort of meditation/retreat thing and trust your inner chi or whatever to rearrange your mind into a better state
3. The option I like: use a crude map of how the mind is organized to take an inventory. Example: https://refactorcamp.org/@vgr/101161647324908468