Houston Tumlin -- the kid who played Ricky Bobby's son in 'Talladega Nights' -- grew up to proudly serve his country, but sadly suffered from PTSD and depression as a result, which led to his suicide ... his mother tells TMZ.
Michelle Tumlin tells us ... her son honorably served in the U.S. Army for nearly 6 years, earning many accolades as an E-4 specialist in the 101st Airborne Division.
Houston's awards include the Army Achievement Medal, National Defense Service Medal and Global War on Terrorism Service Medal, but Michelle says he was most proud of earning his Air Assault wings.