The Disney star entered a treatment centre last November to get help with 'emotional and physical issues'. She checked herself out last month.
A source close to the actress said she is over the worst and is looking forward to getting back to work.
'Demi is in great spirits, a great mood,' the source told Hollywood Life. 'Her treatment really seems to be working and it isn't an act - she's taking her recovery very seriously.'
The 18-year-old, who as well as starring in the Camp Rock films and rPincess Protection Program, has had success as a singer, is expected to release her third studio album later this year.