Answer:
I'd say they play an important role.
Explanation:
I'm not an expert in anyway at all but from what I know... Our genetics is what's passsed down from our parents and so on. So if your parents have a mental illness, the odds of you developing it as well is high. Our life experieces help to also change our mind. For example, if you experienced a life threaqting event... your mind can become changed due to that event. Which then can easily lead to an illness. Esepecially for young minds as they are still growing and learning. This is true even to situations and experiences that aren'y life threating but stressful and depressing.