Access to adequate mental health has always been lacking and inadequate for most people. For decades, even, they get built, funding gets cut, people sneer at the idea of emotions and mental health, and the centers get closed down.
While that is true, it is never a good idea for there to be a gun in the home of a high-risk client, or a stock pile of pills, and other things that a client is strongly encouraged to make inaccessible during a crisis moment (generally by giving these things to a relative to hold onto, or locking them away and letting a relative keep the keys). And for the safety of self and others, disorders that bring on delusions and hallucinations should disqualify someone from owning a gun. If your brain is prone to being fundamentally incapable of distinguishing reality from hallucinations, because your brain is prone to creating them, you don't need a gun. Things can potentially get complicated enough without one.