importance of sleep to mental wellbeing

• Sleep deprivation


  A state caused by inadequate quantity or quality of sleep, either voluntarily or involuntarily
• Sleep quantity


  The amount of time spent asleep - can be measured objectively using time
• Sleep quality


  How well we feel that we have slept/how rested we feel after sleep - can be measured subjectively based on self-report
• Types of sleep deprivation

  • Total sleep deprivation
  • Partial sleep deprivation
• Total/full sleep deprivation


  Going without sleep/staying awake for a 24 hour period (or longer)
• Partial sleep deprivation


  Having a lower quantity of sleep or a lower quality of sleep than is normally required
• REM deprivation


  Inadequate sleep can affect our sleep patterns, with the type of sleep most affected being REM sleep which occurs in higher proportions later in the sleep episode
• Sleep debt


  The accumulated amount of sleep loss from insufficient sleep
• Causes of sleep deprivation

  • Caffeine consumption, food, drugs or alcohol
  • Work or school requirements
  • Failing to wind down before bed
  • Stress
  • Medical conditions
  • An uncomfortable sleeping environment
  • Social influences
• Impacts of sleep deprivation on functioning

  • Most affects are temporary and will abate after recovering any sleep debt
  • Long-term sleep deprivation places the individual at greater risk for a range of diseases and health problems, including obesity, diabetes and various cardiovascular diseases
  • Associated with increased risk of accident and injury
• Affective functioning


  Our ability to control our experience and expression of emotions
• Behavioural functioning


  A person's observable actions
• Cognitive functioning


  A person's mental processing
• Blood Alcohol Concentration (BAC)


  A measure of how much alcohol is in a person's blood stream
• BAC of 0.05


  The legal limit of alcohol in the bloodstream for a full licensed driver in Australia
• BAC of 0.10


  Twice the legal limit
• Dawson and Reid's study found that sleep deprivation and alcohol consumption have similar impairments on cognitive functioning
• Under normal circumstances our internally programmed circadian sleep-wake cycle and the sleep-wake schedule we maintain are closely aligned.
• Circadian rhythm sleep disorders


  A group of sleep disorders involving sleep disruption primarily due to a mismatch between an individual’s sleep-wake pattern and the pattern that is desired or required.
• Circadian rhythm disruption


  • Disrupted and not regulated properly
  • Sleep-wake cycle out of sync with the day-night cycle
  • Changes due to biological issues or lifestyle changes
• Types of circadian rhythm sleep disorders

  • Delayed sleep phase syndrome (DSPS)
  • Advanced sleep phase syndrome (ASPS)
  • Shift work syndrome
• Delayed sleep phase syndrome (DSPS)


  A sleep disorder in which a person’s sleep episode is delayed by two hours or more beyond what is considered an acceptable or conventional bedtime.
• People with DSPS generally have difficulty falling asleep at a ‘normal’ time and waking up at a ‘normal’ time.
• DSPS is the most common circadian rhythm phase disorder, and tends to emerge or worsen during adolescence and into early adulthood.
• Common symptoms of DSPS

  • Sleep-onset insomnia
  • Difficult awakening at the desired or necessary time
  • Excessive sleepiness
• People with delayed sleep phase syndrome who try to work normal work hours become sleep deprived.
• People with DSPS may only get 3 or 4 hours of sleep each night, leading to sleep deprivation affecting their affective, behavioural and cognitive functioning.
• The main problem for people with a persistent delayed sleep phase is their sleep pattern gets out of sync with the day-night cycle and other time cues in the environment.
• People with a delayed sleep phase often compensate by napping during the day or sleeping excessively on weekends.
• Causes of DSPS

  Specific causes are not well understood; some individuals appear to be releasing melatonin later than normal.
• Other causes of DSPS

  • Longer circadian rhythm than normal
  • Increased sensitivity to light at night
• Advanced sleep phase disorder (ASPD)


  A condition where a person has a sleep schedule that consistently runs earlier than desired.
• ASPD is relatively rare, but more common amongst elderly people.
• Common symptoms of ASPD

  • Falling asleep during the late afternoon or early evening
  • Waking up very early in the morning
  • Typical sleep onset times between 6pm - 8pm and wake up times between 1am - 3am
• Causes of ASPD

  Age-related deterioration in the suprachiasmatic nucleus (SCN)<|>Reduction in melatonin production<|>Decreased exposure to light in the late afternoon/early evening
• Similarities between DSPS and ASPD

  • Both are circadian rhythm disorders
  • Both can have difficulty due to receiving less sleep quantity than desired
• Differences between DSPS and ASPD

  • Timing of circadian rhythm
  • Low alertness symptom
  • High alertness symptom
  • Commonly affected persons
  • Prevalence
• Primary symptoms of shift work disorder

  • Insomnia
  • Excessive sleepiness
  • Reduction in total sleep time
• Shift work disorder occurs as a result of work shifts being regularly scheduled during the usual sleep period.
• Shift work

  • Fixed schedules
  • Rotating schedules