insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged and usually abnormal inability to get enough sleep especially due to trouble falling asleep or staying asleep

chronic insomnia

Insomnia is a patient-reported problem characterized by difficulty falling asleep or difficulty maintaining sleep; ie, frequent awakenings, difficulty returning to sleep after awakenings, or awakening too early with inability to return to sleep.

—Daniel J. Buysse

Synonyms of insomnia

• restlessness
• wakefulness
• sleeplessness
• alertness

Examples of insomnia in a Sentence

has suffered from insomnia virtually his entire life

Recent Examples on the Web

So people who have insomnia and are given melatonin by their doctors in an attempt to cope may already be on the way to developing more serious heart problems. —Veronique Greenwood, Time, 10 Nov. 2025

Young users claim excessive screen time has led them to suffer depression, anxiety, insomnia and eating disorders, while others have engaged in self-harm and even died by suicide. —Bloomberg, Mercury News, 7 Nov. 2025

To treat insomnia, the AASM recommends cognitive behavioral therapy (CBT-I), which is considered the gold standard for insomnia treatment. —Helen Carefoot, Flow Space, 5 Nov. 2025

In a review of electronic medical records, thousands of adults who had chronic insomnia and took melatonin for a year or longer had a 90% higher chance of heart failure over the next five years, compared with participants who had the same health factors but didn’t take melatonin. —Kristen Rogers, CNN Money, 4 Nov. 2025

Word History

Etymology

Latin, from insomnis sleepless, from in- + somnus sleep — more at somnolent

First Known Use

1739, in the meaning defined above

Kids Definition

insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged inability to sleep

Medical Definition

insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged and usually abnormal inability to obtain adequate sleep especially due to difficulty falling asleep or staying asleep

called also agrypnia