Psych 3501 Exam 3: Sleep and Circadian Medicine

Sleep continuity: sleep metric

Sleep duration: total amount of time from sleep onset to sleep offset

Sleep onset latency (SOL): amount of time to fall asleep

Wake after sleep onset (WASO): amount of time spent awake from sleep onset to sleep offset

Sleep quality: subjective perception of quality of sleep

Sleep efficiency: sleep duration/time in bed (%)

Healthy: 85%-90% or higher

Sleep stages

Non-rapid eye movement (NREM)

3 stages: stage 1, 2, 3

Progress from lighter to deeper sleep

Rapid eye movement (REM)

Characterized by rapid eye movements, muscle paralysis, and mixed frequency EEG activity

- Prevent us from acting out on our dreams

- EEG activity: similar to an awake brain

Two process model of sleep regulation

The homeostatic sleep drive

As you stay awake, the drive accumulates

The accumulating pressure for sleep drives for sleepiness

During sleep, the pressure decreases

The circadian drive for arousal

24-hour clock in our body, one of the output is circadian wakefulness

Sending the highest alerting signals during mid-day, dropping off at biological night

Most likely to fall asleep when pressure for sleep is high and circadian alerting signal is low

Most likely to wake up when pressure for sleep is low and circadian alerting signal goes up

Circadian rhythms

Describe 24-hour rhythms and multiple processes that keep us in sync with the light/dark cycle

Allow us to anticipate changes in our environment rather than respond passively

the circadian rhythm of melatonin: Low during daytime, have a peak over night

To measure circadian rhythm: measure the time we see the steep rise of melatonin levels

Cognitive Behavior Therapy for Insomnia (CBTI)

Behavioral treatment designed to treat chronic insomnia (unable to fall asleep, stay asleep, wake up too early)

Behavioral model of insomnia

Y-axis: insomnia severity

Threshold: when insomnia symptoms become clinically significant

Premorbid: no insomnia symptoms

Acute: meaningful insomnia symptoms

Early: engage in perpetuating factors

Chronic: precipitating factor goes away, perpetuating behaviors maintaining the insomnia in the long-run

3P model of insomnia

Predisposing: risk factors, things make you more vulnerable to insomnia but don’t cause insomnia on their own

- Genetic risk, medical conditions, mental disorders

Precipitating: stressor in the short-run

- Stressful life event (positive or negative)

- Most people experience in their lives

Perpetuating: behaviors that maintain insomnia over time

- Try to compensate for the sleep loss or to get more sleep

- Spending excessive time awake in bed, going to bed earlier, doing things in bed other than sleep or sex (try to catch sleep)

The problem with perpetuating factors

Mismatch between time in bed and sleep duration

Stimulus dyscontrol

Conditioned arousal

3 core components of CBTI

Stimulus control

Sleep restriction

Sleep hygiene

Stimulus control: playing the odds

Odds 1 in 2: sleep/sex

Odds 1 in 6: sleep/sex/read/eat/worry/work

Complex conditioning history: stimulus paired with many responses

Low probability the stimulus will yield a single given response (sleep)

Stimulus control

Aims to limit amount of time spent in bed/bedroom awake

Instructions:

- Go to bed only when sleepy

- Avoid any behavior in the bed or bedroom other than sleep and sexual activity

- Leave the bedroom if awake more than 15 minutes

- Return to bed only when sleepy

Goal: reduce stimulus dyscontrol; create new conditioning history (bed-sleep instead of bed-awake)

Sleep restriction

Limit sleep opportunity to current sleep duration

Sleep prescription

- Set fixed wake time based on patients weekday needs

- Set bedtime based on average sleep duration

Goals

- Reduced mismatch between time in bed and time asleep

- Increase sleep pressure -> more consolidated sleep

Weekly upward titration by 15 minutes if >90% sleep efficiency

Sleep hygiene

good habits related to sleep

Aims to address problematic sleep-related behaviors/environment

Not effective monotherapy

Example sleep hygiene instructions

- Exercise regularly

- Make sure you bedroom is at a comfortable temperature

- Don’t watch the clock

Optional components

Cognitive therapy

Reduce preoccupation with or anxiety about insomnia

Relaxation/mindfulness

Reduce physiological arousal in the pre-sleep period

Light therapy

Reduce circadian phase delay/advance

CBTI efficacy

Recommended as first-line treatment for insomnia by American College of Physicians

Reduces sleep onset latency and wake after sleep onset by ~50%

60-80% have a therapeutic response to treatment

Improvements stable up to 24 months

Small acute increases in sleep duration but ~1hr increase over long-term follow up

CBTI vs. hypnotics: efficacy

Similarly effective in short-term

CBTI treatment responses maintained up to 24 months

- Long-term: more enduring benefits

Gains from medications diminish after medication cessation

- Hypnotics: more side-effects, tolerance problems

CBTI + hypnotics

adults with insomnia randomly assigned to CBTI alone or CBTI + hypnotics

Conclusion: the combined group has a faster response to treatment compared to CBTI alone, but both groups end up in the same place

Light Therapy

Light has multiple effects: circadian and training effects (directs our circadian clock), but also non-circadian regions of the brain (arousal effect), and mood-related areas of the brain (mood-promoting effect independent of the circadian effect)

time of light exposure

The time at which we receive light exposure affects its impact on circadian clock

Bright light in the morning + dim light in the evening: shift circadian clock earlier

Dim light in the morning + bright light in the evening: shift circadian clock later

The same principle used in light therapy: increase in bright light morning exposure

Light therapy delivery options

Historically: delivered through light boxes: high-intensity lighting

10,000 lux = outdoor natural daylight, 30min-1hr each morning after wake up to receive treatment

Limitation: have to sit in front of the box: burdensome

Recent alternative: wearable light therapy glasses

Benefits: less burden, can continue morning routine

Downsides: much dimmer intensity of light compared to the box (400-500 lux, bright indoor lighting)

Light therapy in seasonal depression

Compared patients with seasonal depression to healthy controls

Baseline: one week of fixed sleep schedule

Two light therapy conditions: bright light 6-8am or 7-9pm

Measure depression symptoms & circadian rhythm using melatonin onset

Compared to baseline week, depression symptoms decreased in both conditions, largest in morning condition compared to evening condition

Patients with seasonal depression have a significant delay pre baseline

In baseline: an advance just by stabilizing the sleep schedule

Morning light condition: further circadian phase advance

Evening light condition: circadian phase moved later

Conclusion: two effects of lights (circadian + mood impact)

Interpersonal and social rhythm therapy (IPSRT)

Developed for bipolar disorders

What are the intervening mechanisms of stressful life events precipitating mood episodes?

Social time cues: interacting with people, eating, etc.

Stressful life events disrupt social time cues (context about time), which impact circadian rhythms, and result in disruption in biological rhythms, which in turn precipitate a mood episode

Interpersonal and social rhythm therapy (IPSRT) component

Interpersonal psychotherapy +

Social rhythm therapy: stabilize social time cues, which in turn stabilizes biological rhythms

Have clients track their social rhythm through social rhythm measure (SRM-5)

Help them construct a daily schedule to stabilize social time cues

IPSRT Efficacy

Efficacious for improving bipolar disorders

BP vs. TAU

T0: baseline; T1: 3-month into treatment; T2: 3-month follow up

A significant reduction in manic symptoms for IPSRT compared to TAU

Increase the amount of time into the next mood episode

Improved regularity of social rhythms

Association between increase social rhythm regularity & reduced likelihood of mood episode recurrence

The role of sleep and circadian medicine in traditional psychotherapy

Sleep disturbance and mental health

Across disorders, medium to large effects for decreased sleep continuity, small to medium to decreased sleep depth, small to medium to increased REM pressure compared to healthy controls

Takeaway: broad association between worse sleep and mental health conditions

Delayed sleep timing associated with blunted response to psychotherapy for OCD

Worse sleep reduces treatment responses for psychotherapies

Later sleep timing (suggesting rhythm delay) is associated to lower response to ERP for OCD

Bedtime at baseline: divided into non-delayed and delayed group

delayed: less reduction in symptoms, more non-responders

Consistent lighting schedules associated with treatment response in residential OCD treatment facilities

Residential facilities for OCD categorize by the average symptom scores of their patients at discharge

Responder facility: the average patient responds to treatment

Non-responder facility: the average patient doesn't respond to treatment

A fixed lighting schedule can have impact on treatment outcomes

Multiple symptoms of psychopathology decrease following CBTI in adolescents

Adolescents with insomnia treated with CBTI (GT)/CBTI over Internet (IT)/waitlist

Both GT and IT significantly decreased mood symptoms that are maintained after 12-month follow-up

Both GT and IT significantly improvements in sleep efficiency

Only treated for insomnia but have improvement on other symptoms

Depression and anxiety decrease following CBTI in pregnant women

Pregnant women with insomnia treated with digital CBTI or TAU

Depression and anxiety decrease from pre to post insomnia treatment and were maintained after 12-month post-treatment follow-up

Suicide ideation decreases following CBTI

Treated with CBTI or control

CBTI reported lower rate of SI at post-treatment and 1-yr follow-up

CBTI enhances PTSD treatment

Treated with CBTI first and then CPT (treatment for PTSD) or control first + CBT

After CBTI/control & after CPT, CBTI has significantly lower depression and PTSD symptoms

Only targeting sleep has significant positive benefits for individual depression and PTSD symptoms

Adding CBTI onto psychotherapy for PTSD improves treatment outcomes

CBTI prevents incidence of depression

Patients treated with CBTI followed over time

Those who were treated with CBTI were less likely to be depressed in the future compared to control

Can leverage CBTI to prevent new depression onset in the future

Summary