Sleep disorders are mental disorders according to the International Classification of Mental Disorders Diagnosis and sleep disorders can often be found in other mental disorders. Sleep disorders refer to disorders in which there are changes in the duration, periodicity of waking and quality of sleep, and there are three main types.
Insomnia, which manifests itself as difficulty falling asleep, excessive dreaming, easy waking and early awakening. Insomnia is one of the most common clinical symptoms and can be caused by a variety of reasons. Some patients do not feel as if they have slept, although they have fallen asleep, and experience severe anxiety, known as subjective insomnia.
Narcolepsy, often caused by debilitation, with some patients exhibiting an irresistible descent into sleep that is brief in duration and easily awakened, is known as episodic sleepiness.
Sleepwalking, also known as somnambulism, refers to patients who get up and move around after a period of sleep during the night, behaving in a dull, dazed manner and not answering questions or answering vaguely. After a period of activity the patient goes back to bed and cannot recall the following day, mostly in children and dysthymia.