The death of University of Georgia student found last month in a creek has been ruled a suicide, the GBI said Wednesday.

Rebecca Elaine Greene, 22, died from a combination of environmental hypothermia and severe intoxication from diphenhydramine, the main ingredient in Benadryl, according to Dr. Kris Sperry, the state’s chief medical examiner.

Greene, of Brunswick, was found Nov. 19 in a creek on The Plaza in west Athens, the morning after she was last seen alive, according to police.

“According to Dr. Sperry, the death occurred when Miss Greene inadvertently fell in to a cold stream after intentionally consuming very large quantities of diphenhydramine,” Sherry Lang, GBI spokeswoman, said in an emailed statement. “Her face and head were not covered by the water, and she did not drown.”

Greene was a chemistry major and philosophy minor at UGA and previously studied at the College of Coastal Georgia and Kennesaw State University. Her funeral was held Nov. 23, according to her online obituary.