VIII. Other Sleep Disorders
This category currently comprises three classifications: Other Physiologic (Organic) Sleep Disorder, Other Sleep Disorder Not Due to Substance or Known Physiological Condition, and Environmental Sleep Disorder.
Other Physiologic (Organic) Sleep Disorder
A disorder is temporarily placed in this category if the cause is not clear, but the expectation is that the disorder is based on physiologic or medical factors.
Other Sleep Disorder Not Due to Substance or Known Physiological Condition
A disorder is placed in this category if it cannot be classified elsewhere in the ICSD-2 and there is a suggestion that the disorder is based on psychiatric or behavioral factors.
Environmental Sleep Disorder
Environmental sleep disorder is also classified here. An environmental sleep disorder is a sleep disturbance caused by the environment, such as a disturbance related to noise, temperature, or other environmental disturbance that leads to daytime fatigue and sleepiness.