You don't have to lie awake for hours past your bedtime to have insomnia. The condition can manifest itself in several ways.

Yes, you may have trouble falling asleep (known as sleep-onset insomnia), but some people have problems staying asleep (sleep-maintaining insomnia) or waking up too early (early morning awakening).

Sleep specialists may look for an underlying cause, such as a medical condition or psychological issue. Here are 11 classifications of insomnia, developed by the American Academy of Sleep Medicine.

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Courtesy of: The American Academy of Sleep Medicine