"I have always been transparent about my journey with addiction. What I've learned is that this illness is not something that disappears or fades with time. It is something I must continue to overcome and have not done yet," she said.
"I want to thank God for keeping me alive and well. To my fans, I am forever grateful for all of your love and support throughout this past week and beyond. Your positive thoughts and prayers have helped me navigate through this difficult time."
"I want to thank my family, my team, and the staff at Cedars-Sinai who have been by my side this entire time. Without them I wouldn't be here writing this letter to all of you," she continued in the statement. "I now need time to heal and focus on my sobriety and road to recovery."
It added, "The love you have all shown me will never be forgotten and I look forward to the day where I can say I came out on the other side. I will keep fighting."
Lovato has talked openly before about her struggle with substance abuse. In June, she released a song called "Sober" about a relapse after six years of sobriety. In the song, she apologized for letting down her family and fans.
In February, she told CBS News that her single, "Tell Me You Love Me," was actually about conquering her addiction as well. "People think it's a breakup song," she said, "but it's actually kind of a breakup song with myself and my bad habits."
In 2016, Lovato told "CBS Sunday Morning" that her four years of sobriety was more important than her career. "Because of that, I'm now sitting here right now, alive and more successful than I've ever been ... Like yes, it's cool that I'm successful, but the most successful thing that I've done is being able to beat my addiction -- and that I'm sitting alive in front of you today."