Scotland's four-times IndyCar champion Dario Franchitti has told the BBC that his first concussion sustained in a racing crash 16-years-ago changed his personality "permanently".
Speaking to presenter John Beattie, the 43-year-old said his easy-going nature was altered after the smash which saw him suffering injuries to discs in his neck.
He explained: "The first time I had a big concussion in 2000 my personality, I felt, completely changed afterwards.
"Years later I brought this up with my brother. I said to Marino [fellow racing driver], I think this happened but he said he hadn't noticed.
"But from the inside it felt different. I just think I was a lot more serious not as easy going [after the crash]."
Franchitti, who is originally from Bathgate and retired from racing three-years-ago, urged anyone who had been concussed to monitor their condition in the long term and to seek help.
"Go and get checked out, you are not a hypochondriac," he added.