Kleine-Levin syndrome (KLS) is a recurrent form of hypersomnia that affects a person three or four times a year. Scientists do not know the cause of this syndrome (like many sleep disorders, it's a disorder of "unknown etiology"). KLS is marked by two to three days of sleeping 18-20 hours per day, an abnormally uninhibited sexual drive, apathy, compulsive eating (hyperphagia or megaphagia), and irritability. Males are three times more likely than females to have the syndrome.
Most people who get KLS are teenage boys. During the few hours a day the person is awake, he or she is lethargic and irritable. Symptoms of Kleine-Levin syndrome break out in episodes. An affected individual may go for weeks or months without experiencing symptoms. The outbreak lasts up to a few weeks or might be over in a few days. Generally teenage KLS patients "outgrow" the syndrome; outbreaks are few and far between as an adult. Even in people who first get KLS as an adult it usually goes away after a decade or so.
There is no good treatment for Kleine-Levin syndrome. Doctors often prescribe Ritalin or modafinil stimulants, and these can relieve the symptoms, but do not affect the underlying problem. (Stimulants can also make the irritability symptom worse.) There is interest in using mood stabilizers such as lithium or carbamazepine although reports indicate these work only in some patients.
Sleep starts are so common that they almost don’t count as a sleep disorder. Most have experienced them - a sudden, often violent, jerk of the entire body or one or more body segments that occurs upon falling asleep. Sleep starts are also known as hypnic or hypnagogic jerks. Somewhat related are: a visual sleep start - usually a sensation of blinding light coming from inside the eyes or head and an auditory sleep start - a loud snapping noise that seems to come from inside the head.
If the fluttering of the eyes during stage R sleep are a visible indication of sleep in the waking world, so also hynic jerks are an intrusion from the waking into the dream world.
Contributing factors that can lead to sleep starts include stress, exercise before bed, and caffeine or other stimulants. Patients that suffer sleep starts often have an iron deficiency and/or a urea buildup. They are also potential side effects of some antidepressants and antihistimines.
At times, many jerks may occur one after another. They can be frequent, intense, and repetitive. Intense or frequent sleep starts may lead to a fear of falling asleep. In most people, they only occur from time to time. Sleep starts are particularly common in young children, although they happen throughout life. The mechanism is not known, but anatomists suspect it is a playing out of a struggle between the part of the brain that promotes waking and the part that promotes sleeping (the VPLO).
The human mind is so narrative-driven that it can make up stories when it feeks sleep starts, and incorporate them into dreams. People sometimes report dreaming of falling or tripping during the hypnic jerks.
They are rarely treated, but if they get bad enough treatment options include leg exercises, iron supplements, and in
bad cases, dopamine agonists similar to those used for restless legs
syndrome, although pregnant women can't have dopamine agonists.
The International Classification of Sleep Disorders includes "toxin induced sleep disorder" which is what it sounds like. It usually manifests as insomnia after a person has ingested a poisonous material. Doctors and sleep scientists rarely call out this disorder anymore. Ingesting a poisonous material is a matter for medical attention, and there may be some secondary insomnia associated with it, but the focus is on detoxification, not on helping the patient sleep.
This dangerous sleep disorder causes patients to stop breathing when sleeping. When awake the person breathes normally. The word hypoventilation means "low breathing" and the person may stop breathing temporarily or permanatly. This congenital condition is very rare.