It was poker that Merson said really helped turn his life around.
"Poker's been a good release for me because gambling is a stimulant," he said.
"That's one of the reasons I worked so hard is because it keeps me clean: It keeps me busy. I love it, and it makes me a good living."
Though he can't imagine quitting poker any time soon, Merson said if he ever leaves the profession, he would like to become a drug counselor.
"That's the only thing that I've been really passionate about other than poker," he said of helping others overcome their addictions.
Merson's mother, Donna Merson, said "not in a million years" did she expect her son would drop out of college, become a professional poker player and be successful.
"You live in Howard County, and you go to Howard County schools and the expectation is you're going to college," she said. "People ask me what my son does, and you say he's a professional poker player, and they kind of look like you like, 'Really?' "
Merson's career choice was not easy for his mother to swallow, especially as she watched him struggle with his drug addiction.
"It was painful to watch, but I'm also just so happy to know that he has the strength to overcome," Donna Merson said through tears.
But ultimately, she sees that poker really was one of the best things that ever happened to her son.
"Poker made him happy, and it basically saved his life," Donna Merson said.
Though it's not all positive — "There have been plenty of ups and downs, and plenty of times I've been on the phone with him when he's lost a lot of money" — Donna Merson said she's OK with her son's career choice.
"Ultimately, kids just have to live their own lives and just be happy about what they do," she said. "And he has supported himself. It's not like he's doing it and asking us for money."
Loving the game
While some may see poker as a game of luck, Merson said there is a lot of skill involved because you're playing against other people, not against the house like in most gambling games.
"A professional is usually going to be pretty smart about what game he should be playing, when he should stop playing the game," he said.
And to play full-time, Merson said, you need to be mentally and physically strong.
"You're using your mind so much … it feels like you've taken a really hard test in college or the SAT or something — just mentally exhausted," he said.
To gain an edge, Merson said he exercises often and eats well.
"Putting good stuff in your body helps with concentration," he said.
Merson can spend 10 or more hours a day playing poker, either online or in tournaments. Exercise, particularly strengthening his core he said, helps when he is sitting without moving for hours on end.
Most of Merson's career has been spent playing online.
"It's pretty normal for me to win or lose five figures in a day on the Internet, any given day," Merson said. "You just get used to the swings after a while."
When the United States government essentially shut down online poker in 2011, Merson decided to move to Toronto, Canada.
"It was one of the hardest days of my life. … It was what I devoted my life to, and now, I can't even live in the country," he said.
Merson recently moved back home to North Laurel after spending the early part of the summer in Las Vegas, competing in the WSOP events. He said he plans to travel and continue playing in tournaments and such until online poker is legalized in the states.
Despite all the ups and downs Merson has experienced from the game, he can't imagine ever giving up poker.
"I still love the game just as much as I did when I was 16 and played it for the first time," he said. "Waking up and doing what you love is the best feeling that you can have."