Suicide Fantasy as a Life-Sustaining Recourse

The suicide literature tends to lump all suicidal ideation together, thereby implying that it is all functionally equivalent. However obvious the claim that suicidal ideation is usually a prelude to suicidal action, some suicidal daydreaming tends to inhibit suicidal action. How are we to distinguish between those daydreams that augur an impending attempt from those that help patients calm down?