Aren’t mentally ill — seriously mentally ill — and delusional people on mind/body-altering drugs already prohibited from owning guns? ... although in Democrat/Communist Party-run California I suppose there’s an exclusion for people who are “transitioning” both themselves and reality ... for “inclusion purposes”, y’know!
All you have to do is check a box stating you’re not mentally ill and have never been institutionalized. If it doesn’t come up on your background check for whatever reason, the gun is yours.