Dr. Ann McKee, the expert at Boston University who conducted the study on Jackson's brain, said the ex-Tampa Bay receiver had "multiple areas of the brain that were affected on both sides of the brain."

McKee noted to "Good Morning America" that oftentimes that level of the disease can lead to "violent behaviors" as well as depression and mood swings.

Jackson's widow, Lindsey Jackson, said in an interview with 'GMA' that she believes it all helps explain how the 38-year-old was found dead in a Florida hotel room back on Feb. 15, 2021.

"In his mind," Lindsey said, "it would have explained why he couldn't fix anything."

Lindsey noted that prior to his death, Vincent was dealing with memory issues and was lashing out often -- and needed alcohol to "feel calm."

She said Vincent told her his brain was "fuzzy" ... but said the booze made it feel "not fuzzy."

Lindsey said in a statement Thursday she's choosing to go public with the diagnosis in order to help others who may be dealing with similar issues.

What's interesting ... Lindsey noted Vincent had never been formally diagnosed with a concussion in his 12-year NFL career.