Miley Cyrus has been sober for six months.
The 27-year-old singer revealed she originally got sober in preparation for vocal surgery but decided to continue it even after the operation because her family has a "history of addiction and mental health challenges".
Speaking on Variety and iHeart podcast The Big Ticket, Miley explained: "I've been sober for the past six months. At the beginning, it was just about this vocal surgery. But I had been thinking a lot about my mother.
"My mom was adopted, and I inherited some of the feelings she had, the abandonment feelings and wanting to prove that you're wanted and valuable. My dad's parents divorced when he was 3, so my dad raised himself. I did a lot of family history, which has a lot of addiction and mental health challenges.
"So just going through that and asking, 'Why am I the way that I am?' By understanding the past, we understand the present and the future much more clearly. I think therapy is great.
"One of my favourite interviews is when I say, 'Anyone that smokes weed is a dummy.' That one I love to send to my parents, who are big stoners, every now and then. It's been really important for me over the last year living a sober lifestyle, because I really wanted to polish up my craft.
"I had really big vocal surgery in November. I had freaking four weeks where I wasn't allowed to talk. I was so ripped writing on the whiteboard, yelling at everybody. I had this one big bicep from just yelling at mom and still trying to do meetings. But it prepared me for the stillness and the quietness."
Miley also revealed that she was worried people would think she was "no fun" when she was sober but the benefits to her lifestyle have been huge.
She explained: "It's really hard because especially being young, there's that stigma of 'you're no fun'. It's like, 'honey, you can call me a lot of things, but I know that I'm fun'. The thing that I love about it is waking up 100 per cent, 100 per cent of the time. I don't want to wake up feeling groggy. I want to wake up feeling ready."
Meanwhile, Miley starred as pop idol Ashley O in Netflix's Black Mirror and revealed she used the upheaval in her personal life - when she and ex-husband Liam Hemsworth lost their home in the Malibu fire - to help her play the character.
She explained: "It was just a really cool experience, being so isolated from my family and friends. I was able to really disconnect from myself, and I was really able to get into Ashley. When Ashley wakes up from the coma and it's totally traumatic, that was the day that I had lost my house in Malibu to the fires.
"I was able to pull from that trauma and use that in the scene. There were times that I had to stop and just go outside and totally melt down.
"It was just a really interesting time for me because so much was falling apart in my personal life, and it was the same thing that was happening in Ashley's life. It gave me a lot to use."