Sleep disorder
A sleep disorder, or somnipathy, is a medical disorder of the sleep patterns of a person or animal. Some sleep disorders are serious enough to interfere with normal physical, mental, social and emotional functioning. Polysomnography and actigraphy are tests commonly ordered for some sleep disorders.
Disruptions in sleep can be caused by a variety of issues, from teeth grinding (bruxism) to night terrors. When a person suffers from difficulty falling asleep and/or staying asleep with no obvious cause, it is referred to as insomnia.
Sleep disorders are broadly classified into dyssomnias, parasomnias, circadian rhythm sleep disorders involving the timing of sleep, and other disorders including ones caused by medical or psychological conditions and sleeping sickness. Some common sleep disorders include sleep apnea (stops in breathing during sleep), narcolepsy and hypersomnia (excessive sleepiness at inappropriate times), cataplexy (sudden and transient loss of muscle tone while awake), and sleeping sickness (disruption of sleep cycle due to infection). Other disorders include sleepwalking, night terrors and bed wetting. Management of sleep disturbances that are secondary to mental, medical, or substance abuse disorders should focus on the underlying conditions.

Common disorders
The most common sleep disorders include:
• Bruxism, involuntarily grinding or clenching of the teeth while sleeping
• Delayed sleep phase disorder (DSPD), inability to awaken and fall asleep at socially acceptable times but no problem with sleep maintenance, a disorder of circadian rhythms. Other such disorders are advanced sleep phase disorder (ASPD), non-24-hour sleep–wake disorder (non-24) in the sighted or in the blind, and irregular sleep wake rhythm, all much less common than DSPD, as well as the situational shift work sleep disorder
• Hypopnea syndrome, abnormally shallow breathing or slow respiratory rate while sleeping
• Idiopathic hypersomnia, a primary, neurologic cause of long-sleeping, sharing many similarities with narcolepsy
• Insomnia disorder (primary insomnia), chronic difficulty in falling asleep and/or maintaining sleep when no other cause is found for these symptoms
• Kleine–Levin syndrome, characterized by persistent episodic hypersomnia and cognitive or mood changes (rare)
• Narcolepsy, including excessive daytime sleepiness (EDS), often culminating in falling asleep spontaneously but unwillingly at inappropriate times. Also often associated with cataplexy, a sudden weakness in the motor muscles that can result in collapse to the floor.
• Night terror, Pavor nocturnus, sleep terror disorder, an abrupt awakening from sleep with behavior consistent with terror
• Nocturia, a frequent need to get up and urinate at night. It differs from enuresis, or bed-wetting, in which the person does not arouse from sleep, but the bladder nevertheless empties.
• Parasomnias, disruptive sleep-related events involving inappropriate actions during sleep, for example sleep walking and night-terrors
• Periodic limb movement disorder (PLMD), sudden involuntary movement of arms and/or legs during sleep, for example kicking the legs. Also known as nocturnal myoclonus. See also Hypnic jerk, which is not a disorder.
• Rapid eye movement sleep behavior disorder (RBD), acting out violent or dramatic dreams while in REM sleep, sometimes injuring bed partner or self (REM sleep disorder or RSD)
• Restless legs syndrome (RLS), an irresistible urge to move legs. RLS sufferers often also have PLMD.
• Shift work sleep disorder (SWSD), a situational circadian rhythm sleep disorder. (Jet lag was previously included, but it doesn't appear in DSM-5 (Diagnostic and Statistical Manual of Mental Disorders).)
• Sleep apnea, obstructive sleep apnea, obstruction of the airway during sleep, causing lack of sufficient deep sleep, often accompanied by snoring. Other forms of sleep apnea are less common. When air is blocked from entering into the lungs, the individual unconsciously gasps for air and sleep is disturbed. Stops of breathing of at least ten seconds, 30 times within seven hours of sleep, classifies as apnea. Other forms of sleep apnea include central sleep apnea and sleep-related hypoventilation.
• Sleep paralysis, characterized by temporary paralysis of the body shortly before or after sleep. Sleep paralysis may be accompanied by visual, auditory or tactile hallucinations. Not a disorder unless severe. Often seen as part of narcolepsy.
• Sleepwalking or somnambulism, engaging in activities normally associated with wakefulness (such as eating or dressing), which may include walking, without the conscious knowledge of the subject
• Somniphobia, one cause of sleep deprivation, a dread/ fear of falling asleep or going to bed. Signs of the illness include anxiety and panic attacks before and during attempts to sleep.

• Dyssomnias - A broad category of sleep disorders characterized by either hypersomnia or insomnia. The three major subcategories include intrinsic (i.e., arising from within the body), extrinsic (secondary to environmental conditions or various pathologic conditions), and disturbances of circadian rhythm.
• Insomnia: Insomnia is often a symptom of a mood disorder (i.e., emotional stress, anxiety, depression) or underlying health condition (i.e., asthma, diabetes, heart disease, pregnancy or neurological conditions).
• Primary hypersomnia. Hypersomnia of central or brain origin.
• Narcolepsy: A chronic neurological disorder (or dyssomnia), which is caused by the brain's inability to control sleep and wakefulness.
• Idiopathic hypersomnia: a chronic neurological disease similar to narcolepsy in which there is an increased amount of fatigue and sleep during the day. Patients who suffer from idiopathic hypersomnia cannot obtain a healthy amount of sleep for a regular day of activities. This hinders the patients' ability to perform well, and the patient has to deal with this for the rest of their lives.
• Recurrent hypersomnia - including Kleine–Levin syndrome
• Posttraumatic hypersomnia
• Menstrual-related hypersomnia
• Sleep disordered breathing (SDB), including (non exhaustive):
• Several types of Sleep apnea
• Snoring
• Upper airway resistance syndrome
• Restless leg syndrome
• Periodic limb movement disorder
• Circadian rhythm sleep disorders
• Delayed sleep phase disorder
• Advanced sleep phase disorder
• Non-24-hour sleep–wake disorder
• Parasomnias - A category of sleep disorders that involve abnormal and unnatural movements, behaviors, emotions, perceptions, and dreams in connection with sleep.
• REM sleep behaviour disorder
• Sleep terror (or Pavor nocturnus)- Characterized by a sudden arousal from deep sleep with a scream or cry, accompanied by some behavioral manifestations of intense fear.
• Sleepwalking (or somnambulism)
• Bruxism (Tooth-grinding)
• Bedwetting or sleep enuresis.
• Sleep talking (or somniloquy)
• Sleep sex (or sexsomnia)
• Exploding head syndrome - Waking up in the night hearing loud noises.
• Medical or psychiatric conditions that may produce sleep disorders
• Psychosis (such as Schizophrenia)
• Mood disorders
• Depression
• Anxiety
• Panic
• Alcoholism
• Sleeping sickness - a parasitic disease which can be transmitted by the Tsetse fly.

Diagnosing insomnia
Insomnia is characterized by an extended period of symptoms including trouble with retaining sleep, fatigue, decreased attentiveness, and dysphoria. To diagnose insomnia, these symptoms must persist for a minimum of 4 weeks. The DSM-IV categorizes insomnias into primary insomnia, insomnia associated with medical or mental illness, and insomnia associated with the consumption or abuse of substances. Individuals with insomnia often worry about the negative health consequences, which can lead to the development of anxiety and depression.
The following tests are used to diagnose insomnia as well as several other sleep disorders.[citation needed]
• Sleep diary: Tracking sleep patterns may help a doctor reach a diagnosis.
• Epworth Sleepiness Scale: a validated questionnaire that is used to assess daytime sleepiness
• Polysomnogram: a test measuring brain and muscle activity including breathing during sleep
• Multiple Sleep Latency Test: a test for daytime sleepiness, usually administered the day after overnight polysomnography
• Actigraphy: a test to assess sleep-wake patterns, usually for a week or more. Actigraphs are wrist-worn devices, about the size of a wristwatch, that measure movement.
• Mental health exam: Because insomnia may be a symptom of depression, anxiety, or another mental health disorder, a mental status exam, mental health history, and basic mental evaluations may be part of the assessment for a person complaining of insomnia.

General principles of treatment
Treatments for sleep disorders generally can be grouped into four categories:
• Behavioral and psychotherapeutic treatment
• Rehabilitation and management
• Medication
• Other somatic treatment
None of these general approaches is sufficient for all patients with sleep disorders. Rather, the choice of a specific treatment depends on the patient's diagnosis, medical and psychiatric history, and preferences, as well as the expertise of the treating clinician. Often, behavioral/psychotherapeutic and pharmacological approaches are not incompatible and can effectively be combined to maximize therapeutic benefits. Management of sleep disturbances that are secondary to mental, medical, or substance abuse disorders should focus on the underlying conditions.
Medications and somatic treatments may provide the most rapid symptomatic relief from some sleep disturbances. Certain disorders like narcolepsy, are best treated with prescription drugs such as Modafinil. Others, such as chronic and primary insomnia, may be more amenable to behavioral interventions, with more durable results.
Chronic sleep disorders in childhood, which affect some 70% of children with developmental or psychological disorders, are under-reported and under-treated. Sleep-phase disruption is also common among adolescents, whose school schedules are often incompatible with their natural circadian rhythm. Effective treatment begins with careful diagnosis using sleep diaries and perhaps sleep studies. Modifications in sleep hygiene may resolve the problem, but medical treatment is often warranted.
Special equipment may be required for treatment of several disorders such as obstructive apnea, the circadian rhythm disorders and bruxism. In these cases, when severe, an acceptance of living with the disorder, however well managed, is often necessary.
Some sleep disorders have been found to compromise glucose metabolism.

Hypnosis treatment
Research suggests that hypnosis may be helpful in alleviating some types and manifestations of sleep disorders in some patients. "Acute and chronic insomnia often respond to relaxation and hypnotherapy approaches, along with sleep hygiene instructions." Hypnotherapy has also helped with nightmares and sleep terrors. There are several reports of successful use of hypnotherapy for parasomnias specifically for head and body rocking, bedwetting and sleepwalking.
Hypnotherapy has been studied in the treatment of sleep disorders in both adults and children.

Sleep medicine
Due to rapidly increasing knowledge about sleep in the 20th century, including the discovery of REM sleep and sleep apnea, the medical importance of sleep was recognized. The medical community began paying more attention than previously to primary sleep disorders, such as sleep apnea, as well as the role and quality of sleep in other conditions. By the 1970s in the USA, clinics and laboratories devoted to the study of sleep and sleep disorders had been founded, and a need for standards arose.
Sleep Medicine is now a recognized subspecialty within internal medicine, family medicine, pediatrics, otolaryngology, psychiatry and neurology in the United States. Certification in Sleep Medicine shows that the specialist:
"has demonstrated expertise in the diagnosis and management of clinical conditions that occur during sleep, that disturb sleep, or that are affected by disturbances in the wake-sleep cycle. This specialist is skilled in the analysis and interpretation of comprehensive polysomnography, and well-versed in emerging research and management of a sleep laboratory."
Competence in sleep medicine requires an understanding of a myriad of very diverse disorders, many of which present with similar symptoms such as excessive daytime sleepiness, which, in the absence of volitional sleep deprivation, "is almost inevitably caused by an identifiable and treatable sleep disorder", such as sleep apnea, narcolepsy, idiopathic hypersomnia, Kleine–Levin syndrome, menstrual-related hypersomnia, idiopathic recurrent stupor, or circadian rhythm disturbances. Another common complaint is insomnia, a set of symptoms which can have a great many different causes, physical and mental. Management in the varying situations differs greatly and cannot be undertaken without a correct diagnosis.
Sleep dentistry (bruxism, snoring and sleep apnea), while not recognized as one of the nine dental specialties, qualifies for board-certification by the American Board of Dental Sleep Medicine (ABDSM). The resulting Diplomate status is recognized by the American Academy of Sleep Medicine (AASM), and these dentists are organized in the Academy of Dental Sleep Medicine (USA). The qualified dentists collaborate with sleep physicians at accredited sleep centers and can provide oral appliance therapy and upper airway surgery to treat or manage sleep-related breathing disorders.
In the UK, knowledge of sleep medicine and possibilities for diagnosis and treatment seem to lag. quotes the director of the Imperial College Healthcare Sleep Centre: "One problem is that there has been relatively little training in sleep medicine in this country – certainly there is no structured training for sleep physicians." The Imperial College Healthcare site shows attention to obstructive sleep apnea syndrome (OSA) and very few other sleep disorders.