Junior Seau Had Brain Disease CTE: Twelve-time Pro Bowl linebacker Junior Seau had a degenerative brain disease when he committed suicide last May, the National Institutes of Health revealed Thursday after conducting a blind study of his brain at his family's request. Seau had abnormalities consistent with chronic traumatic encephalopathy (CTE), the NIH found. "I was not surprised after learning a little about CTE that he had it," said his son Tyler. In private his father was suffering from wild mood swings, irrationality, forgetfulness, insomnia and depression, Tyler said.