Final answer:
Insomnia, sleep apnea, narcolepsy, and parasomnias are common sleep disorders that can be treated using various methods and therapies.
Step-by-step explanation:
Insomnia, a consistent difficulty in falling or staying asleep, is the most common sleep disorder that is treated using various methods. One treatment option for insomnia is cognitive-behavioral therapy, which has shown to be quite effective. Other sleep disorders such as sleep apnea, narcolepsy, and parasomnias also have specific treatment approaches.