psych unit 4

• melatonin is released from the pineal gland.
• the SCN controls and Regulates sleep woke cycle rhythms,
• circadian rhythm refers to the body's internal clock (24 hours) that regulates sleep-wake cycles, hormone release, eating patterns, etc.
• ways to measure sleep- objective measures - Detects Amplifies Record Electrical - EMG(muscle tension) , EOG (eye movement) , EEG(brain waves)
• Subjective measures of sleep - SLEEP dairies, and video monitoring
• Sleep deprivation

  A state caused by inadequate quantity or quality of sleep
• Quantity

  Amount - objective
• Quality


  How well we feel - subjective
• Quantity influences our perception of quality

  E.g. Waking up several times (less quantity) → feeling less rested (less quality)
• Partial sleep deprivation


  A state caused by inadequate quantity or quality of sleep (while getting some sleep in 24 hours) either voluntarily (choosing to stay up late) or involuntarily (having a sleep disorder, experiencing jet lag)
• Total sleep deprivation


  Getting no sleep in a 24 hour period
• Generally, the effects of partial sleep deprivation tend to be minor and temporary when they occur occasionally or in the short-term
• If sleep deprivation persists and daily sleep requirements have not been met over a period of time, a sleep debt may build
• Effects of sleep deprivation

  • Affective effects
  • Behavioural effects
  • Cognitive effects
• Affective effects

  Changes in emotions and emotional responses
• Behavioural effects


  Changes in actions and the ability to control them
• Cognitive effects

  Changes in mental processes
• Affective effects of sleep deprivation

  • Poor emotional regulation; resulting in amplified emotional responses that are out of proportion (exaggerated) in comparison to normal emotional responses
  • Irritability and moodiness
  • Increase in negative emotions
  • Reduced ability to cope with stress
  • Difficulty judging other people's emotions
  • Reduced empathy towards others
  • Increase in aggression and impatience
  • Increase in mood swings
• Behavioural effects of sleep deprivation


  • Sleep inertia (sense of disorientation after waking)
  • Excessive sleepiness during the day
  • Increased likelihood of engaging in risk-taking behaviours
  • Fatigue (lack of energy)
  • Slowed reaction time
  • Reduced efficiency - takes more time to complete tasks
  • Reduced motor control and heightened clumsiness
  • Involuntary lapses into microsleeps
  • Diminished social functioning and impaired control of behaviour
• Cognitive effects of sleep deprivation

  • Difficulty paying attention
  • Impairment of memory
  • Impaired decision-making and problem-solving abilities
  • Diminished creativity and ability to utilise abstract thought
  • Irrational and/or illogical thinking
  • Impaired visual and spatial ability
• Blood alcohol concentration (BAC)

  A measure of how much alcohol is in a person's bloodstream
• BAC 0.05 = 0.05 grams of alcohol for every 100 millilitres of blood in a person's body
• Alcohol is a depressant drug - it slows nervous system functioning and decreases alertness, concentration, reflexes, and decision-making
• Similarities between effects of alcohol and sleep deprivation

  • Affective functioning
  • Cognitive functioning
• Circadian rhythm sleep disorders

  Group of sleep disorders involving a sleep disruption that is primarily due to a mismatch between a person's sleep-wake pattern and the pattern that is desired/required
• Causes of circadian rhythm sleep disorders

  • Naturally occurring change or malfunction in biological mechanisms regulating the sleep-wake cycle
  • Mismatch between a sleep-wake cycle and the sleep-wake schedule required by school, work or social schedule
  • Mismatch between a person's sleep-wake cycle and the day-night cycle of their physical environment
• Delayed Sleep Phase Syndrome (DSPS)


  Condition in which the major sleep episode is delayed in relation to the desired sleep time or what is considered a conventional time
• Symptoms of DSPS

  • Sleep-onset insomnia
  • Difficulty awakening at the desired/necessary time
  • Excessive sleepiness
• When sleep is allowed to occur on the delayed schedule, it is essentially normal in quantity and quality for the person's age - it just occurs at a later time
• DSPS tends to emerge or worsen during adolescence and continue into early adulthood
• DSPS tends to be resistant to many treatment methods
• Some adolescents delay their sleep schedules for social reasons and may not have underlying abnormalities in their circadian rhythm
• DSPS is the most common of all the circadian rhythm phase disturbances, affecting 7-15% of adolescents/young adults
• Advanced Sleep Phase Disorder (ASPD)

  A persistent disturbance of the sleep–wake cycle characterised by advance of the major sleep episode to an earlier time compared to desired or conventional sleep times
• Typical sleep onset times for ASPD are between 6 pm and 8 pm, and wake times are between 1 am and 3 am
• ASPD is a rare disorder, more common in older people (approx 1% of middle age or older)
• Shift work

  A type of work schedule designed to meet the demands of a 24/7 society, divided into "shifts" of about 8 hours – day, afternoon and night (may be fixed or rotating)
• Permanent night shift workers tend to experience more problems with their sleep – difficult to sleep during the day → sleep 1-4 hours less than non-shift workers (= sleep debt)
• Rotating shift work = more disturbances to the sleep-wake cycle
• It is better to work on a particular shift for longer (e.g. 3 weeks not 3-day rotations) as more time is available to 'reset' the sleep-wake cycle