They get out of their deep hole very much on their own, usually within weeks or months. But that's actually the problem in bipolar disorder. They can go from total depression to a much more energetic state in days or a few weeks, such that suicidal ideation and feeling like shit can overlap with high motivational energy. And that's the most dangerous time for suicidal tendencies. In a very deep depressive episodes, suicide is just too much effort.

And yes, I was referring to Lithium as the only medication which significantly reduces the incidence of suicide attempts in bipolar patients. But that effect is only visible long-term.