A sleep disturbance in which one awakens several times during the night and he has difficulty to return to sleep is called

Insomnia is characterized by difficulty falling asleep or staying asleep, resulting in poor sleep quality. The question describes waking several times and trouble returning to sleep, which is maintenance insomnia. Narcolepsy involves sudden sleep attacks, sleep apnea involves breathing interruptions, and somnambulism is sleepwalking.