Would joining the Royal Marines pull me out of suicidal depression?

it wont fix your depression, but it might give you some reasons to start to like yourself. but depression is a chemical thing. the exercise you would get in basic training might reverse your depression though. exercise is probably the number one way to help depression because it replaces some of the chemicals your brain is missing. if you dont feel like possibly risking your life you could just go to the gym every day. but maybe the marines would give you a purpose.