It is a flag for me I am afraid. I think Poly 'can be' really stressful and I don't know if it is a good idea to increase one's life stress by living a more complicated lifestyle but, that is just my opinion.
As it is I have one of those empathic personalities which finds depressive people very difficult to handle, it affects my peace of mind and I am attracted to positivity. I have very little patience with over anxious people either. So I guess I am not really wired to be compatible with a person who has mental health problems.
I realise in the Poly community I am probably a rare bird but that is just me.