if the parents do find a tdoc who makes such a diagnosis as a means of excusing the teens' behavior, then that therapist is unethical and should lose their license.
besides, who are WE to say whether or not these teens are mentally ill? only a trained tdoc or pdoc can determine that.
if truth be told, i feel the same level of frustration towards people who try to use bipolar as an excuse for uncontrollable anger, rage and/or an inability to deal with life's problems (i.e. "i couldn't control my temper and acted that way because i'm bipolar."). bipolar disorder is a *chemical imbalance* -- not an excuse for bad behavior.
when people truly diagnosed with bipolar have problems with impulse control, judgement and/or anger, it is because they have a chemical imbalance that cannot be helped. in other words, they do not choose to act out on these behaviors.