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  • electromyogram (EMG)
  • PPT

    1. 1. Stress Disorders, Sleep Disorders
    2. 2. Stress Disorders <ul><li>Stress (response) : physiological and behavioural reaction caused by the perception of aversive or threatening stimuli (Cannon, 1921). </li></ul><ul><li>Stressors : Environmental triggers of stress </li></ul><ul><li>PTSD requires an identifiable stressor for diagnosis </li></ul><ul><li>Often the association between the stressor and the stress response is not clear </li></ul>
    3. 3. Stress Response <ul><li>Fight or flight response: mobilization of resources to prepare us to face stressors </li></ul><ul><ul><li>Effects of the Hypothalamic-Pituitary-Adrenal axis </li></ul></ul><ul><li>Mobilization of energy in face of the stressors includes: </li></ul><ul><li>Activation of sympathetic nervous system </li></ul><ul><ul><li>increased heart rate, increased muscular contractions, increased blood pressure, decreased digestion/metabolism </li></ul></ul><ul><li>Adrenal hormones are released </li></ul><ul><ul><li>Epinephrine </li></ul></ul><ul><ul><li>Norepinephrine (activation of NE receptors in brain) </li></ul></ul><ul><ul><li>Steroid stress hormones (cortisol) </li></ul></ul>
    4. 4. Stress Response <ul><li>1. Norepinephrine </li></ul><ul><ul><li>Stressful situations (e.g. social isolation in rats) will increase release of NE </li></ul></ul><ul><ul><li>hypothalamus, frontal cortex, and lateral basal forebrain including portions of amygdala (Yokoo et al., 1990, Cenci et al., 1992; van Bockstaele et al., 2001) </li></ul></ul><ul><ul><li>Downregulation of the alpha-2 receptor in response to hight NE levels </li></ul></ul><ul><li>2. Serotonin </li></ul><ul><ul><li>5HT is decreased </li></ul></ul><ul><ul><li>Raphe nucleus, frontal areas involved in extinction </li></ul></ul>
    5. 5. Stress Response <ul><li>3. Glucocorticoids and corticotropin releasing hormone (CRH) </li></ul><ul><li>Receptors throughout the brain (and rest of body) </li></ul><ul><li>Controlled by the hypothalamus, CRH serves as a neuromodulator in the limbic system, periaqueductal gray matter, locus coeruleus, and amygdala </li></ul><ul><li>Injection of CRH into rats’ brains induces fear reactions (Britton et al., 1982) </li></ul><ul><li>Antagonists of CRH reduce anxiety caused by stressors (Heinrichs et al., 1994) </li></ul><ul><li>Heightened activation of sympathetic nervous system </li></ul>
    6. 6. 1. Sufficient sensory information is present for assessment. Vermetten & Bremmer, 2002
    7. 7. 2. Assessment based on access to prior experience. Vermetten & Bremmer, 2002
    8. 8. 3. Encode memory of (potential) threat. Vermetten & Bremmer, 2002
    9. 9. 4. Access to neuroendocrine, autonomic, motor responses. Vermetten & Bremmer, 2002
    10. 10. PTSD: Prevalence, Info <ul><li>Prevalence: 5-10% (U.S), higher in war-torn areas </li></ul><ul><li>Three themes of PTSD: </li></ul><ul><li>Re-experiencing of stressful event </li></ul><ul><li>Avoidance of stimuli </li></ul><ul><li>Persistent, increased arousal </li></ul>
    11. 11. PTSD: Prevalence, Info <ul><li>In adults, traumatic events occur more often to men, but PTSD is 4 times more common in women (Fullerton et al., 2001) </li></ul><ul><li>In children: </li></ul><ul><li>Loss of acquired language skills </li></ul><ul><li>Regression of toilet training </li></ul><ul><li>Somatic complaints (stomachaches or headaches) </li></ul><ul><li>Delayed onset of PTSD often occurs for chronic abuse </li></ul>
    12. 12. PTSD: DSM-IV Criteria <ul><li>The person has been exposed to a traumatic event in which both of the following have been present: </li></ul><ul><li>(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 </li></ul><ul><li>(2) the person's response involved intense fear, helplessness, or horror. </li></ul><ul><li>Note: In children, this may be expressed instead by disorganized or agitated behavior. </li></ul>
    13. 13. PTSD: DSM-IV Criteria <ul><li>B. The traumatic event is persistently re-experienced in one (or more) of the following ways: </li></ul><ul><li>recurrent and intrusive distressing recollections of the event, including images, thoughts, or perceptions. </li></ul><ul><li>Note: In young children, repetitive play may occur in which themes or aspects of the trauma are expressed. </li></ul><ul><li>(2) recurrent distressing dreams of the event. </li></ul><ul><li>Note: In children, there may be frightening dreams without recognizable content. </li></ul>
    14. 14. PTSD: DSM-IV Criteria <ul><li>(3) acting or feeling as if the traumatic event were recurring </li></ul><ul><li>sense of reliving the experience </li></ul><ul><li>illusions, hallucinations, and dissociative flashback episodes </li></ul><ul><li>young children: trauma-specific reenactment may occur. </li></ul><ul><li>(4) intense psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event. </li></ul><ul><li>(5) physiological reactivity on exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event. </li></ul>
    15. 15. PTSD: DSM-IV Criteria <ul><li>C. Persistent avoidance of stimuli associated with the trauma and numbing of general responsiveness (three or more of the following): </li></ul><ul><li>(1) efforts to avoid thoughts, feelings, or conversations associated with the trauma </li></ul><ul><li>(2) efforts to avoid activities, places, or people that arouse recollections of the trauma </li></ul><ul><li>(3) inability to recall an important aspect of the trauma </li></ul><ul><li>(4) markedly diminished interest or participation in significant activities </li></ul>
    16. 16. PTSD: DSM-IV Criteria <ul><li>(5) feeling of detachment or estrangement from others </li></ul><ul><li>(6) restricted range of affect </li></ul><ul><li>unable to have loving feelings </li></ul><ul><li>(7) sense of a foreshortened future </li></ul><ul><li>does not expect to have a career, marriage, children, or a normal life span </li></ul>
    17. 17. PTSD: DSM-IV Criteria <ul><li>D. Persistent symptoms of increased arousal (not present before the trauma), as indicated by two (or more) of the following: </li></ul><ul><li>(1) difficulty falling or staying asleep </li></ul><ul><li>(2) irritability or outbursts of anger </li></ul><ul><li>(3) difficulty concentrating </li></ul><ul><li>(4) hypervigilance </li></ul><ul><li>(5) exaggerated startle response </li></ul>
    18. 18. PTSD: DSM-IV Criteria <ul><li>E. Duration of the disturbance is more than one month. </li></ul><ul><li>F. The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning. </li></ul><ul><li>Specify if: </li></ul><ul><li>Acute: if duration of symptoms is less than 3 months </li></ul><ul><li>Chronic: if duration of symptoms is 3 months or more </li></ul><ul><li>Specify if: </li></ul><ul><li>With Delayed Onset: if onset of symptoms is at least 6 month </li></ul>
    19. 19. Health effects of long term stress <ul><li>Chronic stress is thought to be most problematic for long-term health </li></ul><ul><li>Acute traumatic stress , in a few cases, may be equally as devastating </li></ul><ul><li>(e.g. war, natural disasters, rape, witnessing murder) </li></ul><ul><ul><li>Exacerbation of initial traumatic event </li></ul></ul>
    20. 20. Health effects of long term stress <ul><li>Selye (1976) – long-term effects of stress are caused by chronic release of glucocorticoids </li></ul><ul><ul><li>Increased blood pressure </li></ul></ul><ul><ul><li>Damage to muscle tissue </li></ul></ul><ul><ul><li>Steroid diabetes </li></ul></ul><ul><ul><li>Infertility </li></ul></ul><ul><ul><li>Inhibition of growth </li></ul></ul><ul><ul><li>Inhibition of inflammatory responses </li></ul></ul><ul><ul><li>Suppression of immune system </li></ul></ul><ul><li>Loss of brain tissue </li></ul><ul><ul><li>Elevated levels of CRH in women and men with PTSD (Yehuda, 2001) </li></ul></ul>
    21. 21. Neuropathology <ul><li>volume loss of hippocampus in veterans with combat-induced PTSD (Bremner et al., 1995) </li></ul><ul><li>brain degeneration occurred in people who had been subjected to torture (Jensen et al., 1982) – note: not by experimenters </li></ul><ul><li>Loss is proportional to amount of combat exposure (Gurvits et al. 1996) </li></ul><ul><li>Similar effects in those exposed to severe childhood abuse (Bremner et al, 1999) </li></ul>
    22. 22. Sleep Disorders
    23. 23. Sleep Disorders <ul><li>1 in 8 Canadians suffer from a Sleep Disorder </li></ul><ul><li>May or may not be related to stress </li></ul><ul><li>May be related to undersleeping or oversleeping </li></ul><ul><li>Often comorbid with anxiety or depression </li></ul><ul><li>No age limits for definition </li></ul><ul><li>Often undiagnosed or untreated for years </li></ul><ul><li>Can have profound impact on physical and mental health </li></ul>
    24. 24. What is normal sleep? <ul><li>Waking </li></ul><ul><li>Beta waves: 13-40 Hz, low amplitude, asynchronous </li></ul><ul><li>Alpha waves: 8-13 Hz, higher amplitude (when meditative or relaxed). </li></ul><ul><li>2. Stages 1 and 2 (Light sleep) </li></ul><ul><li>Theta waves: 4-7 Hz </li></ul><ul><li>May not be aware that you fell asleep </li></ul><ul><li>3. Stages 3 and 4 (Heavy sleep) </li></ul><ul><li>Delta waves: < 4Hz </li></ul><ul><li>Sleep walking and talking </li></ul>
    25. 25. What is normal sleep? <ul><li>4. Rapid eye movement (REM) sleep </li></ul><ul><li>Return of alpha and beta activity, like waking states </li></ul><ul><li>Darting eye movements </li></ul><ul><li>Dramatic loss of muscle tone--effectively paralyzed </li></ul><ul><li>Dreaming </li></ul><ul><li>Stage 1 to REM = 90 minutes </li></ul><ul><li>As night progresses, amount of REM sleep increases and stage 3-4 sleep decreases </li></ul>
    26. 26. What is normal sleep?
    27. 27. Disorders of sleep <ul><li>Insomnia </li></ul><ul><li>Narcolepsy </li></ul><ul><li>REM Sleep Behaviour Disorder </li></ul><ul><li>Problems associated with slow wave sleep </li></ul><ul><li>Inability to sleep at night produces many of the same symptoms as the stress response--sleep is critical for neural “recovery” </li></ul><ul><li>Hallmark of all sleep disorders is an inability to maintain normal wakefulness during the day: Excessive daytime sleepiness (EDS) </li></ul>
    28. 28. Insomnia <ul><li>Feeling that you are not getting enough sleep, often associated with anxiety </li></ul><ul><li>May be difficulty falling asleep or early waking, often associated with depression </li></ul><ul><li>Hard to define as people differ in sleep needs </li></ul><ul><li>Often treated with drugs although majority of patients do not undergo a sleep study </li></ul><ul><li>Most drugs are barbiturates which affect GABA receptors (perhaps in reticular activating formation) </li></ul>
    29. 29. Narcolepsy <ul><li>Neurological disorder characterized by sleep at inappropriate times (sleep attack) </li></ul><ul><ul><li>Overwhelming urge to sleep particularly in monotonous conditions </li></ul></ul><ul><ul><li>Sleep appears normal and lasts 2-5 minutes </li></ul></ul><ul><ul><li>Person (temporarily) feels refreshed </li></ul></ul><ul><li>Cataplexy : muscular paralysis while fully awake (similar to paralysis during REM) </li></ul><ul><ul><li>Usually triggered by strong emotion or sudden physical effort </li></ul></ul><ul><li>Hypnagogic hallucinations: seeing and hearing things as one is falling asleep. </li></ul><ul><li>Often skip slow wave sleep at night and move directly to REM from waking </li></ul><ul><li>Caused by low levels or absence of a peptide hypocretin in lateral hypothalamus (Saper et al., 2001) </li></ul>
    30. 30. REM Sleep Behaviour Disorder <ul><li>Typically we are paralyzed during REM sleep </li></ul><ul><li>In some people, this paralysis does not occur, and they act out their dreams without awareness </li></ul><ul><li>Not necessarily the same as sleepwalking, although this may be a component </li></ul><ul><li>Associated with neurodegenerative disorders (such as Parkinson’s) </li></ul><ul><li>Can be associated with brain damage to pons, reticular activating formation (Culebras and Moore, 1989) </li></ul><ul><li>Symptoms are opposite to those of cataplexy </li></ul>
    31. 31. Slow-wave sleep <ul><li>Usually occur during stage 4, when a person is difficult to rouse but not dreaming </li></ul><ul><li>Include: </li></ul><ul><ul><li>Bedwetting (nocturnal enuresis) </li></ul></ul><ul><ul><li>Sleepwalking (somnambulism) </li></ul></ul><ul><ul><li>Night terrors (pavor nocturnis) </li></ul></ul><ul><li>All of these tend to occur more frequently in children – they usually grow out of these </li></ul><ul><li>No association with other mental health disorders </li></ul><ul><li>Not sure of neurobiology as it is difficult to do sleep studies with children </li></ul>
    32. 32. Neuropathology <ul><li>Wake-sleep cycles are regulated by brainstem structures </li></ul><ul><li>Thalamic nuclei (which receive direct visual input from the LGN) </li></ul><ul><li>Suprachiasmatic nucleus: circadian clock </li></ul><ul><li>Ventrolateral preoptic nucleus: wakefulness and vigilance </li></ul><ul><li>2. Other areas </li></ul><ul><li>Raphe nucleus (pons): general arousal </li></ul><ul><li>Locus coeruleus: vigilance, arousal </li></ul>
    33. 33. Neuropathology <ul><li>A host of different medications are used to increase vigilance and altertness </li></ul><ul><li>Epinephrine and its agonists </li></ul><ul><li>Other monoaminergic agonists: Methylphenidate </li></ul><ul><li>Acetylcholine antagonists: Caffeine </li></ul><ul><li>Most medications with sedative effects focus on increasing GABA concentrations (benzodiazepines, barbiturates) </li></ul>