According to the CDC (source), 50-70 Million US adults suffer from some form of insomnia. It has been studied, that adults function otpimally with 7-8 hours of sleep, and 30% of adults will report getting less than 6 hours of sleep.
Reportedly, there are 10 Million adults in the U.S. taking perscription sleeping aids.
According to Traditional Chinese Medicine, there are at least 10 disharmony patterns that an Acupuncturist uses to differentiate the cause for insomnia. The most common ones that I have seen, are Heart Yin Deficiency and Heart and Gallbladder qi deficiency.
Heart Yin deficiency presents with Insomnia with inability to fall asleep easily. Your brain just cannot turn off, and thoughts keep repeating themselves.
Heart and Gallbladder qi deficiency will present with restless sleep, often waking at the same time every night and being unable to fall asleep again.