A disruptive pattern of sleep that may include 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 within 4 main categories:  

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

Problems with staying and falling asleep 

Disorders of difficulty in initiating or maintaining sleep are called insomnias include:

• psychophysiological (learned insomnia)
• delayed sleep phase syndrome
• hypnotic dependent sleep disorder
• stimulant dependent sleep disorder

Problems with staying awake Sleep Apnea

Disorders of excessive sleepiness are called hypersomnias. These include:

• obstructive sleep apnea
• central sleep apnea
• narcolepsy
• restless leg syndrome
• periodic Limb Movement Disorder
• isolated sleep paralysis
• idiopathic hypersomnia
• respiratory muscle weakness associated sleep disorder

Problems with adhereing to a regular sleep schedule

Problems may also occur with maintaining a consistent sleep and wake schedule as a result of disruptions of normal times of sleeping and wakefulness. This occurs when traveling between times zones and with shift workers on rotating schedules, particularly with nighttime workers.

These disorders include:

• jet lag
• sleep state misperception (the person actually sleeps a different amount than they think they do)
• shift work sleep disorder
• natural short sleeper (the person sleeps less hours than "normal" but suffers no ill effects)
• irregular sleep-wake syndrome  

Sleep disruptive behaviors

Abnormal behaviors during sleep are called parasomnias, and are fairly common in children. They include:

• Nightwalking
• Sleep walking
• REM behavior disorder (a type of psychosis can develop related to lack of REM sleep and lack of dreaming)