In an open letter, Shawn, 27, wrote a heartfelt message to "anyone who reads it," in the hope that he could give strength to those struggling with drug abuse.
"I just read the news about Mr. Philip Seymour Hoffman, and against the advice of others, I had to write this open letter," wrote Shawn, referring to the late Oscar-winning actor. Philip, 46, was found dead in his New York apartment on Sunday and is thought to have passed away from a heroin overdose.
"I can't stay quiet anymore about this," continued Shawn. "I am an alcoholic and a drug addict.
"Yesterday I celebrated five months of sobriety. I want to express that I chose to share this about myself because I could not hear of another person being robbed of their life, due to addiction, knowing that I stayed quiet about mine.
"Knowing that if, by sharing my story, I could potentially save a life — and didn't; that I would no longer be able to look myself in the mirror with the same pride I've allowed myself to have, for overcoming the thing that almost took my life."
Shawn then went into detail about the extent of his addiction and how it affected his friends and family.
"For several years, I lived for drugs," he wrote. "I lived for other things as well. But drugs dictated the other things I lived for. I thought more about using, than I thought about any other 'pleasures'. I put myself in places I never would have ended up, otherwise, for the sake of getting high. There are countless nights of blacking out, and making poor decisions as a result of my overusing.
"I worried the people that care about me. My friends. My parents. My siblings. All for the sake of something that I believed I had control over. I didn't even realize how low drugs and alcohol had pulled me."
Shawn then spoke of his pride at overcoming his addiction and the aim behind his revealing message.
"If you're reading this letter, I hope it comes to you with only encouragement," he wrote. "I hope it provides you strength, in the way that I've intended it. Whether you are currently battling an addiction, or have never even sipped a drink.
"I hope it gives you strength to consider the potential it has to take everything, that is dear, from you. I hope you can save your life. Love Shawn."