There are certain terms I can't stand, and one of them is "expert", simply because there are very few fields in which it is possible for someone to know everything about everything. One such field is mental health. I don't like people being put on some kind of podium and called "experts", because there is no way to know everything about mental health.
Put it this way, you can read every textbook about mental health, but you'll never be able to speak to every person with mental health issues. One of the things I stress is that every person is unique, as are their experiences, and that they should be treated as such. Therefore until you meet a person, you're not going to know how they're affected by their mental illness, and they could be affected in ways you've never come across or even thought about.
On one occasion, I've been referred to as an expert, simply because I've lived through my own hell whilst dealing with mental illness. I didn't think much of it at the time, but now it makes my skin crawl. Sure, I've lived through it, but it doesn't mean I'm an expert. I'm an expert in terms of my own experiences, maybe, but I'm not a mental health expert.
In short, no, I don't think there is any such thing as a mental health expert.