Insomnia, which is Latin for "no sleep" is the inability to fall asleep or stay asleep. Insomnia is also used to describe the condition of waking up not feeling restored or refreshed.
Insomnia is the most common sleep complaint among Americans. It can be either acute, lasting one to several nights, or chronic, even lasting months to years. When insomnia persists for longer than a month, it is considered chronic. According to the National Center for Sleep Disorders Research