The actor has suffered from anxiety since childhood, he revealed late Tuesday in a series of tweets promoting awareness of the disorder.
Haynes, 27, shared his story after retweeting an article about a study showing anxiety can affect people’s social status.
“For those of you who are suffering with intense anxiety…ur not alone. It’s been a constant struggle for me since 5th grade. It’s a battle,” he tweeted. “Anxiety had put me in the hospital a countless amount of times. Whether it be fainting, hyperventilating, or seizures…I’ve been through it.”
Colton, who first gained fame as jock Jackson Whittemore on MTV’s Teen Wolf, added that anxiety “affects more [people] than you would ever know” and detailed how he’s even become agoraphobic, or afraid of being in open spaces, and has lived “in constant fear” of leaving his home.
VIDEO: Arrow‘s Colton Haynes Reveals Secrets from the Set
“I’ve quite jobs because of anxiety, flaked on social events, family gatherings, birthdays, important movie/work tests. Its a serious problem,” he said. “Be there for those who struggle with anxiety & realize its a serious disorder. Its not a case of ‘being dramatic’…its a life long struggle.”
His posts on the topic have gotten thousands of retweets and likes.
Arrow airs Wednesday at 8 p.m. ET on The CW.