A lot of people in the RPG mental health field do a lot of talking about LARPing, and while I don't have any experience in that, I can attest to the power of cosplay.
I cosplayed for about 20 years, but one of my favorite and most notable cosplays was the Scout from Team Fortress 2. Gearing up for this cosplay, I started doing distance running (The scout is a runner class), and began to look at the Scout's dialogue and mannerisms so I could get into character. The scout is a cocky, hyper-caffeinated, arrogant jerk who thinks he's better than everyone out there.
At a time when I was dealing with a lot of really low self confidence, this was a godsend. I was able to incorporate parts of the Scout that I needed into myself, and for the weekends when I was able to do those cosplays, I felt amazing. I walked around with this swagger that was absolutely fake, but it gave me practice in just having that self confidence. Of being able to tell people off if I needed to. To feel like I was awesome. To feel like the coolest guy in the room.
And that had staying power.
I've heard countless stories from my friends in the cosplay community of how cosplay has changed their life- from building a healthy sense of community to giving them a sense of purpose and a clear goal, as well as allowing them to explore an identity. There's also some toxic things in the cosplay community, largely tied to social media, body image issues, the rise of the professional/competitive cosplayer, etc- but a lot of these things can be tied to geek culture getting big and corporate. There's still a space for people to like a character, put together a costume, and get to be that person for a weekend with their friends.
There's something incredibly liberating about getting to make believe you are someone for a weekend, while being in that person's costume. To look into the mirror and not see yourself, but see that character, and say to yourself, "I am so and so." To be free of your fixed identity, and get to be someone else for a short while.
And the lessons you learn there can be invaluable in helping you improve your identity. You get to be that character you like, and then keep the parts of them you enjoyed being. For me, when I was Scout, I kept the confidence, and that helped make me the person I am today.
I'd love to hear about how cosplay changed your life. Feel free to chat me up at @rollforkindness on twitter!