Lovato, 25, a Grammy-nominated recording artist, was "okay and stable, reported People magazine, quoting an unidentified source".
A Los Angeles Police Department spokesman said officers were called to an address in Hollywood at around 11.40am local time.
Emergency services brought Demi back to consciousness using Narcan, a medication which blocks the effects of opioids.
TMZ adds that Demi's aunt, Kerissa Dunn, posted on social media that Demi is "awake and responsive" a little after 3 p.m. today.
"Wilmer is completely devastated and he still loves Demi and it was just a matter of scheduling and time that they needed to make a romantic relationship work. PLEASE PRAY she pulls through".
Lovato had apparently been out on Monday night celebrating a friend's birthday. She's been in and out of the rehab for alcoholism and drug abuse in the past but she bounced back to resume her singing career and earlier this year, completed six years of sobriety.
GOP lawmaker resigns after making racist comments on ‘Who Is America?’
Later, after the credits, footage showed Spencer using a racial epithet to refer to inhabitants of the Middle East. Spencer also says he was so distracted by his fears that racist slurs spilled from his mouth at Cohen's behest.
Twitter Users Burn Eric Trump For Inaccurately Spinning Presidential Poll
He has previously boasted that Mr Putin thought he was a "genius" and said "getting along with Russian Federation is a good thing".
Tekashi69 Hospitalized After Being Kidnapped, Pistol-Whipped & Robbed
On Sunday, 6ix9ine, also known as Tekashi 6ix9ine , dropped "FEFE," his new musical collaboration with Nicki Minaj . Rapper Tekashi69 is recovering in hospital after he was robbed and attacked in NY on Sunday morning.
The "Sorry Not Sorry" singer has always been vocal about her struggles with drug addiction, and last month revealed via song that she had relapsed after six years of sobriety. "I'm sorry that I'm here again, I promise I'll get help/ It wasn't my intention, I'm sorry to myself", Lovato sings at one point.
In 2011, she entered a facility, where she was treated for bipolar disorder, bulimia, self-harm, and addiction. She chronicled her daily struggles with recovery in the 2017 YouTube original documentary "Simply Complicated".
"My dad was an addict and an alcoholic. If it weren't for my friends, family, and fans, I wouldn't be here today".
"I started to choke a little bit and my heart started racing".
Speaking as part of a YouTube documentary a year ago, she spoke about her use of cocaine.
In a statement, a representative for the star said: "Demi is awake and with her family who want to express thanks to everyone for the love, prayers, and support".