My belief is that willpower isn't something a person "just" needs - it's one of most precious and hard to acquire things a person can have. It also doesn't fix mental health problems, but it helps cope with them. I say that as someone who has just barely enough willpower to keep my own life from falling apart, even with medication and the help of my family. I don't know how to get more of it so I'm not going to be dismissive of other people who also don't have as much as they might want.