Garrison died at his Arizona home in early March.
Garrison Brown's official cause of death has been confirmed.
According to an autopsy report obtained by ET from the Coconino County Medical Examiner, the 25-year-old son of Janelle and Kody Brown died from a gunshot wound to the head on March 5 at his Flagstaff, Arizona, home. His manner of death has been ruled a suicide.
The report also notes that the Sister Wives star's blood alcohol level (BAL) was as high as .370% and that ethanol intoxication -- aka alcohol poisoning -- is considered a contributing factor in the death.
According to the University of Rochester, a BAL of .3% or greater causes a person to be in a "stupor" and have "little comprehension of where you are." A BAL of .35% or greater "also happens to be the level of surgical anesthesia. You may stop breathing at this point."
Flagstaff Police Department confirmed in a statement to ET back in March that they were dispatched to Garrison's residence and found him dead after being called by his younger brother, Gabriel. Garrison appeared to have suffered a self-inflicted gunshot wound, cops shared at the time.
Just hours after Garrison's death was first reported, Janelle and Kody -- who split in 2022 after nearly 30 years of their spiritual marriage -- released a statement confirming the news and sharing their heartbreak over the loss of their third son and fourth child together.
"Kody and I are deeply saddened to announce the loss of our beautiful boy Robert Garrison Brown," the statement read. "He was a bright spot in the lives of all who knew him. His loss will leave such a big hole in our lives that it takes our breath away."
Kody posted the same message to his own account, tweaking the language to read, "Janelle and I are deeply saddened."
In the two months since, Janelle, 55, has used her social media page to memorialize her son, who would have turned 26 in early April.
Around the time of his birthday, the reality TV star posted a heartbreaking tribute to Garrison, in which the grieving mom of six shared photos and videos of her son on his birthday throughout the years.
"Happy Birthday Sweetheart. We are missing you terribly today. It's hard to believe you aren't here anymore," she wrote in the caption, accompanied by a whistled version of "Happy Birthday."
She continued, "We talked a lot about you today and even went to Texas Roadhouse for dinner (your favorite place 😀)... I still feel you nearby sometimes. And I'm grateful we will see each other again when my journey is completed."
Janelle has also found comfort in her devoted fanbase who have stood by her and offered support through the difficult ordeal. She has reciprocated the love by keeping her followers updated on her healing progress, sharing photos from Garrison's celebration of life event, showing off the last family photo with all of her kids and speaking about how she has found comfort in her faith.
Back in March, she posted pics from a North Carolina beach where she was staying with her daughter, Maddie, telling fans that she was celebrating Easter by spending some time with her grandkids. Maddie, Janelle's eldest daughter, married Caleb Brush in 2016 and the pair shares kids Axel, 6, Evangalynn, 4, and Josephine, 1.
"Happy Easter everyone!" Janelle captioned the photos. "I have been even more grateful for my faith this year. The remembrance of the Savior and His gift of eternal life."
If you or someone you know is considering suicide, please contact the National Suicide Prevention Lifeline at 1-800-273-TALK (8255), text "STRENGTH" to the Crisis Text Line at 741-741 or go to suicidepreventionlifeline.org.
RELATED CONTENT:
