May 8 (UPI) -- Former NFL quarterback Johnny Manziel was hospitalized in Texas following a "scary" reaction to medication he takes for bipolar disorder.
Manziel revealed the specifics of his Humble, Texas, hospital stay Tuesday on social media. The 25-year-old was admitted Monday night.
"Thank you everyone for your concern and kind messages," Manziel wrote on an Instagram story. "Unfortunately I had a reaction to an increased dosage in Lithium which I take for my Bipolar disorder. It was a scary moment and I'm especially grateful for the staff at the hospital and all that they've done in the last 24 hours."
Manziel was in the area attending the JMBLYA concert with his friends after participating in a golf tournament hosted by former Texas A&M teammate Mike Evans. Tampa Bay Buccaneers quarterback Jameis Winston, Charles Sims, Donovan Smith, Elandon Roberts, Eric Ebron, Damontre Moore, Ryan Swope, Dante Hall and Tra Carson also participated in the charity event.
Manziel -- who hasn't taken an NFL snap since the 2015 season with the Cleveland Browns -- has been putting his skills on display for NFL scouts and team executives this offseason, in hopes of returning to the league.