I know, first hand, how strong the illusion is, that depression causes. It’s like having a mountain poised to avalanche down on you. You just want to escape, even if it’s via extreme means.

The key is that it is still an illusion. It’s a paper tiger, once you get a handle to fight it, it dissolves like mist. Most people who attempt suicide, due to mental health, are not dealing with a steady chronic condition. They are at a crisis point. If they receive appropriate help, clawing their way back is perfectly possible for most.

There are exceptions, but they are quite rare. I would bundle them with terminal illness, though proving that is a lot harder. It’s also a balancing act between being OK with dying, and being of sound mind to make that decision.

Many places make it illegal to allow police to intercede. In most places, the police can intervene if they believe a crime is about to be committed.

There is a huge line between someone who is terminally ill, and wants to die on their own terms, and someone having a mental health crisis. The first should be legal, but still needs support and checking, the 2nd need immediate help.