And if tonight my soul may find her peace
in sleep, and sink in good oblivion,
and in the morning wake like a new-opened flower
then I have been dipped again in God, and new-created.
~D.H. Lawrence

The sleep disorders can classified as:

INSOMNIA (Lack Of adequate Sleep)

Disorder of insufficient quantity/quality of sleep. Prevalence rises with age and can be as much as 40% in the elderly. ICD 10 diagnoses Non Organic Insomnia (without obvious medical cause) as:
A. A complaint of difficulty falling asleep, maintaining sleep, or non refreshing sleep.
B. The sleep disturbance occurs at least three times per week for at least one month.
C. The sleep disturbance results in marked personal distress or interference with personal functioning in daily
living.
D. Absence of any known causative organic factor, such as a neurological or other medical condition,
psychoactive substance use disorder or a medication.

Treatment includes advice regarding sleep hygiene. Hypnotics like valium (Diazepam) should only be used in extreme cases and only for very short spells, as there is a risk of dependence.

HYPER-SOMNIA (EXCESSIVE SLEEPING)

The commonest type is Narcolepsy. This is not an uncommon disorder with prevalence rates similar to that for Multiple Sclerosis. It is primarily a disorder of REM sleep wherein the latency to REM sleep is abnormally short (usually less than 5 minutes)
The clinical symptoms are diagnostic and consist of:
1) Excessive daytime sleepiness and sleep attacks
2) Cataplexy, presents with sudden episode of muscle weakness triggered by intense emotions like anger, fear and laughter.
3) Sleep paralysis the patient suddenly finds himself unable to move for a few minutes, most often upon falling asleep or waking up
4) Hypnagogic hallucination patients experience dream-like auditory or visual hallucinations, while dozing or falling asleep.
 
Sleepiness is treated with amphetamine-like stimulants, while the symptoms of abnormal REM sleep (cataplexy, sleep paralysis, hypnagogic hallucinations) are treated using antidepressants.

SOMNAMBULISM (Sleep Walking)

Slightly more common in females and is mainly seen in children between the ages of 5 to 12.
This is a state of altered consciousness where a person walks while asleep. The patient is difficult to awaken during this time. Contrary to popular belief, it is unlikely for the individual to indulge in complex behaviors like homicide. ICD 10 criteria includes:

A. Repeated (two or more) episodes in which the individual gets up from sleep with a panicky scream and intense anxiety, body motility and autonomic hyperactivity, (such as tachycardia, heart pounding, rapidbreathing and sweating).
B. The episodes occur mainly during the first third of sleep.
C. The duration of the episode is less than ten minutes.
D. If others try to comfort the individual during the episode there is lack of response followed by
disorientation and preservative movements.
E. Limited recall of the event.
F. Absence of any known causative organic factor, such as a neurological or other medical condition, psychoactive substance use disorder or a medication.

Management includes making the immediate environment of the patient safe to avoid injury and at times, small doses of hypnotics. Patients usually outgrow of this disorder.

NIGHT TERRORS

Usually seen in childhood but start in adulthood. Disorder of stages 3 & 4 of NREM wherein patients wake up terrified and screaming but do not remember it the next morning. ICD 10 diagnostic criteria is:

A. Repeated (two or more) episodes in which the individual gets up from sleep with a panicky scream and
intense anxiety, body motility and autonomic hyperactivity, (such as tachycardia, heart pounding, rapid
breathing and sweating).
B. The episodes occur mainly during the first third of sleep.
C. The duration of the episode is less than ten minutes.
D. If others try to comfort the individual during the episode there is lack of response followed by
disorientation and perseverative movements.
E. Limited recall of the event.
F. Absence of any known causative organic factor, such as a neurological or other medical condition, psychoactive substance use disorder or a medication.

Management for children is usually reassurance while for adults there is evidence for Paroxetine, Diazepam and Psychotherapy.

NIGHTMARES

These ouccer in the REM part of sleep and are remembered by the patient on waking up. ICD 10 diagnoses these as:

A. Awakening from nocturnal sleep or naps with detailed and vivid recall of intensely frightening dreams,
usually involving threats to survival, security or self-esteem. The awakening may occur during any time of
the sleep period, although they typically occur during the second half.
B. Upon awakening from the frightening dreams, the individual rapidly becomes oriented and alert.
C. The dream experience itself and the disturbance of sleep resulting from the awakenings associated with the
episodes cause marked distress to the individual.
D. Absence of any known causative organic factor, such as a neurological or other medical condition, psychoactive substance use disorder or a medication