Demi Lovato joked being a Disney star gave her post traumatic stress disorder (PTSD).

She said: "We joked around that it was Disney High, except we all were shooting shows and really overworking.

"I joke that I sometimes have PTSD after leaving the channel, because if my schedule starts to get too busy, I rebel and I get bitchy."

However Demi admitted she was the one who used to push herself so hard because she had so many ambitions she wanted to achieve.

She told Billboard magazine: "I always wanted to be the next Shirley Temple, to be the youngest person to ever win a Grammy and an Oscar. It didn't turn out that way."

And though the 'Skyscraper' singer - who previously battled with alcohol and drug abuse, self harm and an eating disorder - doesn't regret her younger years, she'd think twice about allowing her future children to get into the same situation.

She said: "I don't regret it, but I probably won't allow my kids to get into the industry unless it's on their terms."

In 2010, Demi left a Jonas Brothers tour after punching a dancer and subsequently checked into rehab, and though she has been very close friends with Nick Jonas for several years, she was too embarrassed for a long time to speak to him again.

She admitted: "I distanced myself as I was getting involved with self-destructive things. After treatment, I had to have some time sober before I wasn't embarrassed to talk to him.

"Nick says I sent text messages, but I don't remember s**t.

"The first time we saw each other since that tour was my [2012 Los Angeles] concert at The Greek. We caught up right before the show, then performed. It was an emotional reunion - I got one of my best friends back.

Meanwhile, Nick - who is currently on a joint tour with Demi - admitted he was "angry" with his pal both because he worried about her mental state, but also the possible financial repercussions of her leaving the tour.

He said in the joint interview: "I thought we were going to get sued. I mean, it was bad. On top of losing a friend, we have seven dates left, it's a big production, people are expecting to see Demi and that's not going to happen. I was angry, because a week before I pleaded with her to confide in me. We talked on the plane for two hours."

Demi added: "Really? To be totally honest, I don't remember that. It's unfortunate I had to go through that stuff in order to appreciate what I have in front of me."