Final answer:
Grace most likely suffers from insomnia, which is the most common sleep disorder, characterized by difficulties in falling or staying asleep. Insomnia requires these symptoms to occur at least three nights a week for a one-month period.
Step-by-step explanation:
The most common sleep disorder that Grace has been diagnosed with is likely insomnia. Insomnia is characterized by consistent difficulty in falling or staying asleep. Individuals with insomnia often experience long delays in going to bed and actually falling asleep, wake up several times during the night, and have trouble getting back to sleep.
These symptoms should be present for at least three nights a week for at least one month. Other sleep disorders, such as sleepwalking, narcolepsy, and sleep apnea, have their own distinct symptoms and issues.
For example, sleep apnea involves pauses in breathing during sleep, while narcolepsy is characterized by an irresistible urge to fall asleep during waking hours.