Demi might seem like a positive and likable person, but beneath the wonderful demeanour lies a restless personality.
The Heart attack hit maker has a condition known as Bipolar Disorder.
Bipolar disorder , formerly manic depression, is a mental disorder with periods of depression and periods of elevated mood. The elevated mood is significant and is known as
mania or hypomania, depending on its severity, or whether symptoms of psychosis are present. During mania an individual behaves or feels
abnormally energetic, happy or irritable. Individuals often make poorly thought out decisions with little regard to the consequences. The need for sleep is usually reduced during manic phases. During periods of depression there may be crying, a negative outlook on life, and poor eye contact with others. The risk of suicide among those with the illness is high at greater than 6 percent over 20 years, while self-harm occurs in 30-40 percent.  Other mental health issues such as anxiety disorders and substance use disorder are commonly associated.
After she revealed her struggles with this problem, she has become more vocal and active on it. As a matter of fact, she released an album called ‘ Confident’ which was a reference to her long-term condition.
Other celebrities with rare conditions include Lil Wayne, Selena Gomez and Bill Gates.