Circadian and rhythm sleep disorders

What is a sleep disorder

• A condition where sleep problems cause distress, deviate from normal sleep-wake patterns, or disrupt daily functioning

Are sleep disorders limited to one type of problem

• No, they are broad and include many different types of sleep-related problems

What are circadian rhythm sleep disorders

• Sleep disorders that disrupt the normal regulation of the circadian rhythm, altering the sleep-wake cycle

Which specific circadian rhythm sleep disorders will be discussed

• Delayed Sleep Phase Syndrome (DSPS)

• Advanced Sleep Phase Disorder (ASPD)

• Shift work disorder

What fundamentally causes circadian rhythm sleep disorders

• A disruption to the typical sleep-wake cycle

What are examples of causes of circadian rhythm sleep disorders

• Biological issues (like adolescent sleep-wake shifts) and lifestyle changes (such as shift work)

What common outcome do circadian rhythm sleep disorders tend to cause

• Sleep deprivation

What are some emotional and physical effects of circadian rhythm sleep disorders

• Amplified emotional responses, fatigue, irritability, and reduced ability to concentrate

How can circadian rhythm sleep disorders disrupt an individual’s lifestyle

• By causing late arrivals to commitments and feeling sleepy at abnormal times, making daily tasks difficult

What is Delayed Sleep Phase Syndrome (DSPS)

• A circadian rhythm sleep disorder where sleep and waking occur later than usual

How does DSPS affect the typical sleep-wake cycle

• The sleep-wake cycle is delayed, so sleep and wake times shift later than normal

Give an example of how DSPS changes sleep times

• Instead of sleeping from 10pm to 8am, a person with DSPS may sleep from 1am to 11am

What causes DSPS

• Misalignment between external cues (like light) and internal biological cues regulating the circadian rhythm

How does melatonin secretion relate to DSPS?

• Melatonin is secreted later than usual, causing later sleep and wake times

What is Advanced Sleep Phase Disorder (ASPD)

• A circadian rhythm sleep disorder where sleep and waking occur earlier than usual

What causes ASPD

• Misalignment between external cues (received appropriately) and internal cues, causing early melatonin secretion

How does melatonin secretion affect ASPD

• Melatonin is secreted earlier, leading to earlier sleep and wake times

What is the key difference between DSPS and ASPD

• DSPS involves later melatonin secretion and delayed sleep times; ASPD involves earlier melatonin secretion and earlier sleep times

What is shift work

• An occupation that involves working at unusual hours, often outside the typical 9-to-5 schedule

How does shift work affect sleep times

• Individuals may need to sleep at unusual times, such as during the day instead of at night

What is rotating shift work

• Working different shifts in rotation, such as a week of morning shifts followed by a week of night shifts

Name some occupations that often involve shift work

• Nurses, road workers, hotel staff, and drivers

How does shift work impact the sleep-wake cycle

• It causes the circadian rhythm to constantly change and adapt, disrupting normal patterns

Is shift work considered a sleep disorder

• No, it is considered a cause of sleep problems, potentially leading to circadian rhythm sleep disorders or other issues

What is insomnia

• A sleep disorder characterized by difficulty falling asleep and staying asleep

How does shift work cause fragmented sleep

• Sleeping at unusual hours leads to waking up repeatedly and having multiple short sleep episodes instead of one continuous sleep period

What is a circadian rhythm phase disorder related to shift work

• When external environmental cues are out of sync with work requirements, like being in bright light at night

How does shift work affect sleep quality and quantity

• Both can be negatively affected because the body is programmed to sleep at night and be awake during the day

What causes ASPD and DSPS compared to shift work disorders

• ASPD and DSPS are caused by problems with internal cues, while shift work disorders are caused by problems with external cues (like light exposure)

What is bright light therapy

• A method to adjust a person’s circadian rhythm through exposure to a high-intensity light source

How does morning bright light exposure affect the body

• It signals the suprachiasmatic nucleus (SCN), promoting wakefulness through cortisol release and triggers earlier melatonin release at night

What role does the suprachiasmatic nucleus (SCN) play in bright light therapy

• It acts as a biological clock regulator by receiving light as an external cue to adjust the sleep-wake cycle

How does bright light therapy readjust the circadian rhythm

• By ensuring sleeping and waking occur at the desired times through gradual exposure

How long and how often are bright light therapy sessions typically conducted

• Sessions last from about 15 minutes to a couple of hours, up to a few times a day, for several consecutive days

Why are bright light therapy sessions done over several consecutive days

• To gradually shift the sleep-wake cycle by adjusting exposure time each day to reach the desired waking time

Why is the timing of bright light exposure important

• Exposure must occur at the right time to help a person feel awake and adjust their sleep-wake cycle appropriately

Give an example of appropriate timing for bright light therapy

• Someone who feels sleepy early (e.g., 5pm) might use bright light in the late afternoon or early evening to stay awake longer

What is important about the amount of light used in therapy

• The intensity and length of exposure must fit the person’s disorder and be built up gradually to avoid side effect

Why should bright light exposure be built up gradually

• To avoid negative side effects like headaches

What safety measures should be taken during bright light therapy

• Do not look directly at the light, and maintain an adequate distance between the face and the light source

How is bright light therapy used to treat Delayed Sleep Phase Syndrome (DSPS)

• Exposure to bright light in the morning promotes wakefulness and signals earlier melatonin release for an earlier sleep time

How does bright light therapy help Advanced Sleep Phase Disorder (ASPD)

• Exposure to bright light in the evening promotes wakefulness later, delaying melatonin release and shifting sleep time later

How does bright light therapy help with shift work-related sleep disorder

• Exposure before a shift promotes wakefulness during work and helps shift sleepiness to a suitable time afterward

What role does the suprachiasmatic nucleus (SCN) play in bright light therapy for these disorders

• The SCN receives light as an external cue to regulate cortisol and melatonin release, adjusting sleep-wake timing