I believe it would depend there are variations on both arguments. Generally speaking nature argument would be that due to genetics or other predispositions bipolarism would be present no matter if the child has interventions, is adopted by anouther family etc. It basically is there or not and no outside factors cause it or stop it. Nuture argument would state that the environment people, community, food etc would impact and determine if someone would become bipolar if a certain combination of triggers where in the individuals life. In the same regard in the nurture theory interventions and even possibly stopping bipolarism would be possible. While nurture family etc has no real part in it besides perhaps changing intensity of ups and downs once the person is concieved and genetic makeup is determined before birth.