Download Stress Disorders Sleep Disorders

Stress Disorders,
Sleep Disorders
PSY4080 6.0D
Stress Disorders, Sleep Disorders
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Stress Disorders
 Stress (response): physiological and
behavioural reaction caused by the perception of
aversive or threatening stimuli (Cannon, 1921).
 Stressors: Environmental triggers of stress
 PTSD requires an identifiable stressor for
diagnosis
 Often the association between the stressor and
the stress response is not clear
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Stress Disorders, Sleep Disorders
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Stress Response
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Fight or flight response: mobilization of resources to
prepare us to face stressors
• Effects of the Hypothalamic-Pituitary-Adrenal axis
 Mobilization of energy in face of the stressors includes:
1. Activation of sympathetic nervous system
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increased heart rate, increased muscular contractions,
increased blood pressure, decreased digestion/metabolism
2. Adrenal hormones are released
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Epinephrine
Norepinephrine (activation of NE receptors in brain)
Steroid stress hormones (cortisol)
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Stress Disorders, Sleep Disorders
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Stress Response
1. Norepinephrine
• Stressful situations (e.g. social isolation in rats) will
increase release of NE
• hypothalamus, frontal cortex, and lateral basal forebrain
including portions of amygdala (Yokoo et al., 1990, Cenci et
al., 1992; van Bockstaele et al., 2001)
• Downregulation of the alpha-2 receptor in response to
hight NE levels
2. Serotonin
• 5HT is decreased
• Raphe nucleus, frontal areas involved in extinction
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Stress Response
3. Glucocorticoids and corticotropin releasing hormone (CRH)
 Receptors throughout the brain (and rest of body)
 Controlled by the hypothalamus, CRH serves as a
neuromodulator in the limbic system, periaqueductal gray
matter, locus coeruleus, and amygdala
 Injection of CRH into rats’ brains induces fear reactions
(Britton et al., 1982)
 Antagonists of CRH reduce anxiety caused by stressors
(Heinrichs et al., 1994)
Heightened activation of sympathetic nervous system
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1. Sufficient sensory information is present for assessment.
Vermetten & Bremmer, 2002
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2. Assessment based on access to prior experience.
Vermetten & Bremmer, 2002
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3. Encode memory of (potential) threat.
Vermetten & Bremmer, 2002
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Stress Disorders, Sleep Disorders
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4. Access to neuroendocrine, autonomic, motor responses.
Vermetten & Bremmer, 2002
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PTSD: Prevalence, Info

Prevalence: 5-10% (U.S), higher in war-torn
areas
Three themes of PTSD:
1. Re-experiencing of stressful event
2. Avoidance of stimuli
3. Persistent, increased arousal
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PTSD: Prevalence, Info
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In adults, traumatic events occur more often to
men, but PTSD is 4 times more common in women
(Fullerton et al., 2001)
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1.
2.
3.
In children:
Loss of acquired language skills
Regression of toilet training
Somatic complaints (stomachaches or headaches)
 Delayed onset of PTSD often occurs for chronic
abuse
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PTSD: DSM-IV Criteria
A. The person has been exposed to a traumatic event in
which both of the following have been present:
(1) the person experienced, witnessed, or was confronted with
an event or events that involved actual or threatened
death or serious injury, or a threat to the physical integrity
of self or others
(2) the person's response involved intense fear, helplessness,
or horror.
Note: In children, this may be expressed instead by
disorganized or agitated behavior.
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PTSD: DSM-IV Criteria
B. The traumatic event is persistently re-experienced in one
(or more) of the following ways:
(1) recurrent and intrusive distressing recollections of the
event, including images, thoughts, or perceptions.
Note: In young children, repetitive play may occur in
which themes or aspects of the trauma are expressed.
(2) recurrent distressing dreams of the event.
Note: In children, there may be frightening dreams
without recognizable content.
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PTSD: DSM-IV Criteria
(3) acting or feeling as if the traumatic event were recurring
 sense of reliving the experience
 illusions, hallucinations, and dissociative flashback episodes
 young children: trauma-specific reenactment may occur.
(4) intense psychological distress at exposure to internal or
external cues that symbolize or resemble an aspect of the
traumatic event.
(5) physiological reactivity on exposure to internal or external
cues that symbolize or resemble an aspect of the traumatic
event.
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PTSD: DSM-IV Criteria
C. Persistent avoidance of stimuli associated with the
trauma and numbing of general responsiveness (three or
more of the following):
(1) efforts to avoid thoughts, feelings, or conversations
associated with the trauma
(2) efforts to avoid activities, places, or people that arouse
recollections of the trauma
(3) inability to recall an important aspect of the trauma
(4) markedly diminished interest or participation in significant
activities
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PTSD: DSM-IV Criteria
(5) feeling of detachment or estrangement from
others
(6) restricted range of affect
 unable to have loving feelings
(7) sense of a foreshortened future
 does not expect to have a career, marriage,
children, or a normal life span
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PTSD: DSM-IV Criteria
D. Persistent symptoms of increased arousal (not
present before the trauma), as indicated by two
(or more) of the following:
(1)
(2)
(3)
(4)
(5)
difficulty falling or staying asleep
irritability or outbursts of anger
difficulty concentrating
hypervigilance
exaggerated startle response
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PTSD: DSM-IV Criteria
E. Duration of the disturbance is more than one month.
F. The disturbance causes clinically significant distress or
impairment in social, occupational, or other important
areas of functioning.
Specify if:
Acute: if duration of symptoms is less than 3 months
Chronic: if duration of symptoms is 3 months or more
Specify if:
With Delayed Onset: if onset of symptoms is at least 6 month
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Health effects of long term stress
 Chronic stress is thought to be most
problematic for long-term health
 Acute traumatic stress, in a few cases, may be
equally as devastating
(e.g. war, natural disasters, rape, witnessing
murder)
• Exacerbation of initial traumatic event
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Health effects of long term stress
 Selye (1976) – long-term effects of stress are
caused by chronic release of glucocorticoids
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Increased blood pressure
Damage to muscle tissue
Steroid diabetes
Infertility
Inhibition of growth
Inhibition of inflammatory responses
Suppression of immune system
 Loss of brain tissue
• Elevated levels of CRH in women and men with PTSD
(Yehuda, 2001)
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Neuropathology
 volume loss of hippocampus in veterans with
combat-induced PTSD (Bremner et al., 1995)
• brain degeneration occurred in people who had
been subjected to torture (Jensen et al., 1982) –
note: not by experimenters
• Loss is proportional to amount of combat
exposure (Gurvits et al. 1996)
• Similar effects in those exposed to severe
childhood abuse (Bremner et al, 1999)
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Sleep Disorders
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Sleep Disorders
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1 in 8 Canadians suffer from a Sleep Disorder
May or may not be related to stress
May be related to undersleeping or oversleeping
Often comorbid with anxiety or depression
No age limits for definition
Often undiagnosed or untreated for years
Can have profound impact on physical and
mental health
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What is normal sleep?
1. Waking
 Beta waves: 13-40 Hz, low amplitude, asynchronous
 Alpha waves: 8-13 Hz, higher amplitude (when meditative
or relaxed).
2. Stages 1 and 2 (Light sleep)
 Theta waves: 4-7 Hz
 May not be aware that you fell asleep
3. Stages 3 and 4 (Heavy sleep)
 Delta waves: < 4Hz
 Sleep walking and talking
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What is normal sleep?
4.
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Rapid eye movement (REM) sleep
Return of alpha and beta activity, like waking states
Darting eye movements
Dramatic loss of muscle tone--effectively paralyzed
Dreaming
Stage 1 to REM = 90 minutes
As night progresses, amount of REM sleep increases and
stage 3-4 sleep decreases
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What is normal sleep?
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Disorders of sleep
1.
2.
3.
4.
Insomnia
Narcolepsy
REM Sleep Behaviour Disorder
Problems associated with slow wave sleep
•
Inability to sleep at night produces many of the same
symptoms as the stress response--sleep is critical for
neural “recovery”
Hallmark of all sleep disorders is an inability to maintain
normal wakefulness during the day: Excessive daytime
sleepiness (EDS)
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Insomnia
 Feeling that you are not getting enough sleep,
often associated with anxiety
 May be difficulty falling asleep or early waking,
often associated with depression
 Hard to define as people differ in sleep needs
 Often treated with drugs although majority of
patients do not undergo a sleep study
 Most drugs are barbiturates which affect GABA
receptors (perhaps in reticular activating
formation)
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Narcolepsy
 Neurological disorder characterized by sleep at
inappropriate times (sleep attack)
• Overwhelming urge to sleep particularly in monotonous
conditions
• Sleep appears normal and lasts 2-5 minutes
• Person (temporarily) feels refreshed
 Cataplexy: muscular paralysis while fully awake (similar to
paralysis during REM)
• Usually triggered by strong emotion or sudden physical effort
 Hypnagogic hallucinations: seeing and hearing things as
one is falling asleep.
 Often skip slow wave sleep at night and move directly to
REM from waking
 Caused by low levels or absence of a peptide hypocretin in
lateral hypothalamus (Saper et al., 2001)
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REM Sleep Behaviour Disorder
 Typically we are paralyzed during REM sleep
 In some people, this paralysis does not occur,
and they act out their dreams without awareness
 Not necessarily the same as sleepwalking,
although this may be a component
 Associated with neurodegenerative disorders
(such as Parkinson’s)
 Can be associated with brain damage to pons,
reticular activating formation (Culebras and
Moore, 1989)
 Symptoms are opposite to those of cataplexy
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Slow-wave sleep
 Usually occur during stage 4, when a person is difficult to
rouse but not dreaming
 Include:
• Bedwetting (nocturnal enuresis)
• Sleepwalking (somnambulism)
• Night terrors (pavor nocturnis)
 All of these tend to occur more frequently in children – they
usually grow out of these
 No association with other mental health disorders
 Not sure of neurobiology as it is difficult to do sleep studies
with children
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Neuropathology
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1.
a.
b.
2.
a.
b.
Wake-sleep cycles are regulated by brainstem
structures
Thalamic nuclei (which receive direct visual input
from the LGN)
Suprachiasmatic nucleus: circadian clock
Ventrolateral preoptic nucleus: wakefulness and
vigilance
Other areas
Raphe nucleus (pons): general arousal
Locus coeruleus: vigilance, arousal
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Neuropathology
A host of different medications are used to
increase vigilance and altertness
a. Epinephrine and its agonists
b. Other monoaminergic agonists: Methylphenidate
c. Acetylcholine antagonists: Caffeine
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Most medications with sedative effects focus on
increasing GABA concentrations
(benzodiazepines, barbiturates)
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