Nikita is always tired. she goes to bed at about 10:30 every night and is asleep in seconds, but she wakes up frequently during the night. she is most likely suffering from

I believe the answer is Insomnia

Insomnia is a form of the medical disorder that makes an individual has a difficulty to obtain proper sleep.

The cause of insomnia could vary between each patient, ranging from psychological, diet, or even hormonal.