Which sleep disorder often involves the acting out of dreams?

The sleep disorder that often involves acting out dreams is REM sleep behavior disorder. This condition is characterized by a loss of the normal paralysis that occurs during REM (rapid eye movement) sleep, allowing individuals to physically act out their dreams. This can result in a range of behaviors, from mild movements to more intense actions such as yelling, hitting, or running.

In REM sleep, muscle atonia typically prevents any physical movement, thus protecting the sleeper from acting out dreams. However, in REM sleep behavior disorder, this protective mechanism fails, leading to potential injury to the individual or their sleep partner during episodes. The dreams that are acted out are often vivid and can be aggressive or violent, reflecting the content of the dream.

Other options represent different types of sleep disorders but do not primarily feature the enactment of dreams in the same way. For instance, narcolepsy involves excessive daytime sleepiness and sudden sleep attacks, sleep apnea is characterized by interruptions in breathing during sleep, and sleepwalking occurs primarily in non-REM sleep and does not involve the complex storytelling found in dreams. Thus, REM sleep behavior disorder is the most accurate choice with respect to the specific behavior of acting out dreams during sleep.