Sleep disorders

Sleep disorders involve any difficulties related to sleeping, including difficulty falling or staying asleep, falling asleep at inappropriate times, excessive total sleep time, or abnormal behaviors associated with sleep.

More than 100 different disorders of sleeping and waking have been identified. They can be grouped in four main categories:

• Problems with falling and staying asleep
• Problems with staying awake
• Problems with adhering to a regular sleep schedule
• Sleep-disruptive behaviors

PROBLEMS WITH FALLING AND STAYING ASLEEP

Insomnia includes any combination of difficulty with falling asleep, staying asleep, intermittent wakefulness and early-morning awakening. Episodes may be transient (come and go), short-term (lasting as long as 2 to 3 weeks), or chronic (long-lasting).

Common factors associated with insomnia include:

• Physical illness
• Depression
• Anxiety or stress
• Poor sleeping environment such as excessive noise or light
• Caffeine
• Alcohol or other drugs
• Use of certain medications
• Heavy smoking
• Physical discomfort
• Daytime napping
• Counterproductive sleep habits:
  • Early bedtimes
  • Excessive time spent awake in bed

Disorders include:

• Psychophysiological insomnia (learned insomnia)
• Delayed sleep phase syndrome -- where a patient's internal clock is constantly out of synch with the "accepted" day / night phases; for example, patients feel best if they can sleep from 4AM to noon
• Hypnotic-dependent sleep disorder -- insomnia resulting from building tolerance to, or stopping, certain types of sleep medications
• Stimulant-dependent sleep disorder -- insomnia resulting depending on, or stopping, certain types of stimulants

PROBLEMS WITH STAYING AWAKE

Disorders of excessive sleepiness are called hypersomnias. These include:

• Sleep apnea
• Narcolepsy
• Restless leg syndrome
• Periodic limb movement disorder
• Obstructive sleep apnea
• Central sleep apnea
• Idiopathic hypersomnia
• Respiratory muscle weakness associated sleep disorder

Sleep apnea more commonly affects obese people, but it may affect anyone with a short neck or a small jaw, regardless of weight. The disorder causes breathing to stop intermittently during sleep, resulting in the person being awakened repeatedly. People with sleep apnea often have difficulty achieving prolonged deep sleep. This results in excessive daytime sleepiness.