The 30-year-old's toxicology report revealed a mix of four drugs as details surface about her final words to Carrey.
Cathriona White's death has officially been ruled a suicide.
Jim Carrey's girlfriend was found dead in her home on Sept. 28 and on Tuesday, her autopsy report from the Los Angeles County Coroner's office confirmed the death was caused by "multiple drugs effect." A toxicology report found four prescription drugs in her system: a mix of painkillers, beta blockers and a sleep aid.
According to the autopsy report obtained by ET, three of the prescriptions were prescribed under the name "Arthur King." The coroner also reported finding a text on White's phone from Carrey the night before she died, asking if she knew where certain painkillers prescribed to him went.
"Given this, it appears likely that the bottles for 'Arthur King' found on [White's] bedside table were the prescriptions he was referring to," the coroner writes.
The coroner also provides details about the letter and note addressed to Carrey found at White's home. The letter requested her belongings be sold and the money be given to family and deferred instructions for her burial service to Carrey. Another sealed note was more personal and addressed her and Carrey's breakup.
Carrey and White dated on and off for three years, starting in 2012. At the time of her death, the actor said he was "shocked and deeply saddened." "She was a truly kind and delicate Irish flower, too sensitive for this soil, to whom loving and being loved was all that sparkled," he said.
EXCLUSIVE: Jim Carrey Speaks Out Following Garry Shandling's Death: 'He Was an Excellent Man'
Carrey served as a pallbearer at White's funeral, which was held at Our Lady of Fatima Church in the village of Cappawhite in her homeland of Ireland on Oct. 10. Around 200 people gathered to sing and pray during the ceremony.
The Eternal Sunshine of the Spotless Mind star made his first public appearance in the wake of White's death at this year's Golden Globes awards, where he ad-libbed jokes about himself and his career. Watch the moment in the video below.
If you or someone you know needs help, please call the National Suicide Prevention Lifeline at 1-800-273-TALK (8255).