Psychology Chapter 7 - Importance of Sleep in Mental Wellbeing

Sleep disturbance

Any sleep-related problem that disrupts an individual's normal sleep-wake cycle. Disruption may be temporary, occasional or persistent

Sleep disorder

Any sleep disturbance that is persistent and regularly disrupts sleep, causing distress or impairment in important areas of everyday life during normal waking hours.

Primary sleep disorder

A persistent sleep disturbance that cannot be attributed to another condition, such as another sleep disorder, physical or mental health issues, or drugs. I.e. this sleep disorder is the main cause of the disturbances.

Secondary sleep disorder

A sleep disturbance that is a by-product of or results from another condition, or use of a substance.

Sleep deprivation

Inadequate quantity or quality of sleep

Partial sleep deprivation

Inadequate quantity or quality of sleep than what is normally required for an individual's needs.

Sleep quantity vs sleep quality

Quantity - amount slept (objective)

Quality - how well we feel after sleep (subjective, but interruptions are also considered)

Total sleep deprivation

Not having any sleep at all over a short-term or long-term period.

Sleep debt

The accumulated amount of sleep loss from insufficient sleep

The ABCs of sleep deprivation effects

Affective - emotions, feelings

Behavioural - actions

Cognitive - thoughts, mental processes

Affective effects of partial sleep deprivation

- inability to regulate emotions

- amplified + inappropriate emotional responses

- difficulties interpreting others' emotions

- increased irritability and poor situation judgement

- depressed mood

Behavioural effects of partial sleep deprivation

- Sleep inertia is more likely to occur if following poor sleep or abrupt awakening

- Slower reaction time

- Excessive sleepiness + fatigue

- Difficulty concentrating

- Reduced efficiency + awareness

- Microsleeps

- Risk-taking behaviour

Microsleeps

A very short period of involuntary sleep, usually lasting 1-15 seconds. Eyes can be closed or open, and person may have no awareness that they slept.

Cognitive effects of partial sleep deprivation

- Reduced alertness and focus

- Difficulty sustaining and dividing attention (especially for boring tasks)

- Irrational thinking

- controlled tasks less affected than automatic tasks

- Delayed response time

- Difficulties being creative and thinking abstractly

- Difficulties problem solving

- Memory and learning impaired

Dawson and Reid (1997)

identified a significant relationship between fatigue due to a moderate level of sleep deprivation, legal levels of alcohol consumption and impaired performance

BAC

Blood-alcohol concentration, a measure of alcohol in the body expressed as grams of alcohol/100 mL of blood

BAC 0.05 =

17 hours sleep deprivation

BAC 0.10 =

24 hours sleep deprivation

Cognitive effects of alcohol intoxication

•Slower thinking

•Decrease in logical thinking and reasoning

•Decreased awareness of perceptual stimuli

•Reduced concentration

How do the affective effects of high BAC and sleep deprivation differ?

High BAC - Positive or negative mood state (i.e. variable)

Sleep deprivation - Negative mood state

Do sleep deprivation and alcohol influence consciousness in the same way?

No, sleep deprivation, alcohol, cognition, concentration and mood are intertwined and may interact in complex ways in influencing conscious experience.

Behavioural effects of different BAC

Circadian rhythm sleep disorders

Sleep disorders involving sleep disturbance that is primarily due to a mismatch between an individual's sleep-wake pattern and the pattern that is desired or required.

Possible causes of circadian rhythm sleep disorders

- A naturally occurring change or a malfunction of biological mechanisms or processes regulating the sleep-wake cycle e.g. DSPS in adolescence

- Mismatch between sleep-wake and environmental day-night cycle e.g. jetlag

- Mismatch between sleep-wake cycle and schedule required by work/school/social schedule

DSPS

Delayed Sleep Phase Syndrome/Disorder. A circadian rhythm sleep disorder in which the major sleep episode is delayed in relation to the desired sleep time or what is considered a conventional time. Occurs more commonly than ASPS and Shift worker disorder. Tends to be relatively treatment resistant.

Symptoms of DSPS

- Sleep-onset insomnia

- Difficulty awakening at the desired or necessary time

- Excessive sleepiness

DSPS in adolescents

7-15% of adolescents are believed to have biologically-driven DSPS.

ASPS

Advanced Sleep Phase Syndrome/Disorder. A circadian rhythm sleep disorder in which the major sleep episode is advanced in relation to the desired or conventional sleep time. Quite rare, and occurs more among older people. Generally more resistant to treatment than DSPS.

Why is ASPS more prevalent in the elderly?

Possibly due to decreased light exposure during the day, a degradation of the SCN, or a biological shift of melatonin release 2-4 hours earlier.

Symptoms of ASPS

•Falling asleep too early

•Struggling to stay awake in the evening

•Excessive sleepiness in the afternoon / evening

Shift work disorder

A circadian rhythm sleep disorder that occurs as a result of work shifts being regularly scheduled during the usual sleep period, requiring adjustment of sleep and wake times to the work times. Tend to lose 1-4 hours of sleep on average.

Fixed vs rotating shift schedule

Fixed - Employees work the same shift on an ongoing, regular basis

Rotating - Employees change shifts evert so often

Symptoms of Shift work disorder

- Insomnia when trying to go to sleep

- Excessive sleepiness when alertness is required

What shift work situations are more likely to cause shift work disorder?

- Permanent night shift (may cause sleep to occur in two parts and to not feel as restful)

- Rotating rosters (especially rotated more frequently than every 3 weeks)

- Roster rotated against the clock

Why is a shift schedule that rotates with the clock better than one that rotates against?

Because the sleep-wake cycle is slightly longer than 24 hours, workers can adapt better as their cycle is less disrupted.

Bright light therapy

A technique for treating circadian rhythm sleep disorders that uses timed exposure of the eyes to light (e.g. using a light box) with the aim of shifting an individual's sleep-wake cycle to a desired, more appropriate or conventional schedule.

3 important variables of bright light therapy

Using the light at the right time of day, at the right intensity for the right amount of time.

Bright light therapy for DSPS, ASPS and shift work disorder

DSPS - early morning hours, e.g. between 6-8am.

ASPS - evening/night

Shift work disorder - (for night shift) evening, and avoiding light in the day; (to adjust to day shift) morning. Can be difficult to correct.

Sleep hygiene

Practices that tend to improve and maintain good sleep and full daytime alertness. Includes behaviours and environmenetal factors.

Sleep hygiene education

Often used in conjunction with therapies to assist people to change sleep-related activities that may add to sleep issues.

Good sleep hygiene practices

> Establishing a regular relaxing schedule and bedtime routine

> Associate your bed/bedroom with sleep

> Avoid stimulating activities before bed (e.g. vigorous exercise, screens, important discussions, stimulants)

> Getting up when you can't sleep

> Exercise to promote good sleep

> Don't eat within 2 hours of bedtime (hunger is circadian too)

> Ensure adequate exposure to daylight

> Good temperature in room (17-19 degrees) (body temp is circadian too)

Mnemonic for sleep hygiene practices

Regular bed stimulates getting up to exercise, eat, look at the light and feel the temperature.

Entrainment

The process of adjusting or resetting a biological rhythm to align with external cues or an environmental cycle (e.g. sleep-wake cycle adjusting to day-night cycle through influence of a zeitgeber)

How does sleeping in daylight affect NREM sleep?

It can cause an increase in the duration of NREM stage 1 sleep, less deep sleep and therefore more shallow sleep and more fragmented sleep.

How does blue light affect NREM and REM sleep

It can cause reduced amount of NREM deep sleep and REM sleep, and increase awakening frequency, and cause morning sleepiness.

Circadian rhythm of thermoregulation

Body temp gradually falls 2 hours before sleep onset, and continues to lower during the night time sleep phase, then rises during the waking phase. Sleep is more likely to occur at cooler temperatures.

Effects of having a warm bath/shower before bed

Promote relaxation that shorten sleep onset, increase initial sleep cycle length and promote more NREM 3 sleep.

Why do stimulants like caffeine make it hard to sleep?

Because they stimulate the CNS, increasing heart rate and suppressing melatonin. It also takes 4-6 hours for the body to break down caffeine.

How does alcohol affect sleep?

While inducing drowsiness and sleep onset, it can lower sleep quantity and quality (especially in 2nd half of night - more awakenings, night sweats, nightmares, headaches)

How can a sleep disturbance become a sleep disorder?

If it becomes persistent and regular, and causes distress to the individual or impairs their ability to function in everyday life.

How can eating patterns affect sleep?

It is important to consistently change eating patterns in order to suit the desired or required sleep-wake cycle.