Do People BECOME BIPOLAR? OR Are They BORN BIPOLAR?

Do People BECOME BIPOLAR? OR Are They BORN BIPOLAR?
My sister became bipolar (after an untimely start into drinking, which is still underway). She says they put in the picture her that's whats wrong with her but surrounded by order for the meds to help out you have to not drink. That doesn't look potential to happen anytime soon. I still pray for her though.
They BORN BIPOLAR
Very upright question.
One of my instructors during my psych rotation put it this mode. Each one of us is born with weed seed in our genetic blusher. If proper conditions are met, those weeds sprout and grow.
People who hold bipolar disorder have a genetic predisposition to it. If persuaded environmental conditions are met, the disorder manifests itself.
Some inhabitants believe that mental health issues can be passed on from one classmates to another. Though most develops as they age--vary by environment and lifestyle.
Im pretty sure people are born bipolar but surrounded by some cases it arises later within their lifes because of some trumatic stress or something