My sister is clinically diagnosed with BPD and has always threatened suicide whenever anyone makes her feel unworthy. 

The issue is any little small disagreement makes her feel that way. Now, she has always had someone to fall back on whether it’s me, other siblings, mother or friends. 

Well this is the first time she has no one to fall back on. She pushed and cut off every single person in her life. 

Is this a sure sign of suicide?