Mary Richardson Kennedy, the estranged wife of Robert F. Kennedy Jr., had three antidepressants in her system but no alcohol when she hung herself at her Bedford, N.Y., home in May.
Kennedy was found to have trazodone, venlafaxine and desmethylvenlafaxine in her system at the time of her death, according to a report released Friday by the Westchester County Medical Examiner's Office.
The couple's divorce was pending at the time of Kennedy's death. According to court filings, Kennedy Jr. had asked that his wife be sober when in the presence of the couple's four children and to not threaten suicide, The Associated Press reported.
Kennedy Jr. filed for a divorce in 2010, one day after police responded to the Kennedy home for a "domestic incident" during which Mary Kennedy allegedly was intoxicated.
Three days later, Mary Kennedy was stopped outside of a school after she steered her Volvo station wagon over a curb, according to reports. She was charged with driving while intoxicated after her blood alcohol level was reported to be 0.11 percent, above the legal limit of 0.08 percent.
The next month, August 2010, she was arrested again for driving under the influence of drugs, according to the AP.
"She struggled so hard, for so long, with mental illness, which so many Americans suffer with," said Kerry Kennedy, her sister-in-law and longtime friend. "She fought with dignity, and in the end, the demons won."
Mary Richardson Kennedy was buried at the Kennedy family compound Hyannisport, Mass.
ABC News' Christina Ng contributed to this report