both parents w/schizophrenia/mental health issues?

Two of my 3 kids are full bio siblings. Both bio parents had mental illness which was due to either genetics or drug or alcohol abuse, one will never really know. Bio mother has committed suicide a few years back and bio father struggles to hold his world together as he still abuses substances. Bio Father has a fairly placid type of personality which I see in my son. Bio Mother was very highly strung, always agitated and aggro but had moments of being warm and friendly. This trait is very similar to my daughter. My daughter is now 13 and is displaying increasing aggression, anger and volatile behaviour. She can be sweet and loving but unfortunately the other side overshadows this. We walk on egg shells around her. We are currently considering medication which is a huge step for us, we said we would never use it but it seems this may be the only alternative to get her life back on track. Nurture can only do so much, nature definitely has a huge role to play when it comes to mental health. I should also mention that my husbands Mother suffered from bi polar disorder and although her children have not gone down the same road, they have had deep depression which they have helped with medication and managed to get on top of. I enjoy reading all of your posts. Lyn