Diagnosed concussions, however, are not reliable indicators of C.T.E. About 20 percent of people found to have C.T.E. had never had a diagnosed concussion, according to doctors at the C.T.E. Center at Boston University, who analyzed Jackson’s brain.
A more direct association are the thousands of smaller, subconcussive hits that Jackson would have absorbed in his two decades of practices and games. Players cope with these hits in any number of ways — painkillers, recreational or medical marijuana and other treatments. According to his widow, Vincent Jackson’s relief was alcohol. Late in his career, she said, he told her that his brain “felt fuzzy” at times and that alcohol cleared it up.
Dr. Ann McKee, the professor of neurology and pathology at Boston University School of Medicine who diagnosed Jackson’s C.T.E., described the damage to his brain in clinical terms. It had “mild frontal lobe atrophy” and a “split in the internal membrane” that could be from the trauma of playing football, she said. There were multiple lesions, mostly in the frontal cortex of his brain.
McKee and Lindsey Jackson put that damage into everyday terms. She said that, beginning with his final year in the N.F.L., her husband began to forget conversations. He showed symptoms of depression for about six months after leaving the league, and without the structure of the football season, he no longer had to temper his drinking. By 2018, when he was 35, his attention span had diminished and he had difficulty solving problems. She said he became paranoid, shutting the blinds when he was home.
Like many former professional athletes, Jackson also grappled with the emotional torment of leaving one life filled with euphoric highs and bruising lows every Sunday for another, more sedate existence with time to stew over unresolved aspirations.
While he made the playoffs four times with the San Diego Chargers, he never played in a Super Bowl, and the Buccaneers never made the postseason and had only one winning season during his five-season tenure with Tampa Bay.