Category: Circadian Rhythm

Everyone at some point knows the pain of a sleepless night. For some, though, this is an all too frequent occurrence. A few quick facts:

• 10% of adults (and 22% of the elderly) have insomnia disorder[ref]
• Heritability estimates from twin studies show that insomnia is around 50% genetic; genes lending susceptibility along with environmental factors. [ref] Another study broke this down further, finding that most genetic influence is on the type of insomnia where people have a hard time staying asleep, rather than difficulty falling asleep. [ref]
• 80-90% of people with major depression experience insomnia of some sort, with about half of them experiencing severe insomnia. [ref]
• Insomnia can be either a problem with initially falling asleep or with waking up in the early morning hours and not being able to fall back to sleep.