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Biological Rhythms and Sleep DISORDERS OF SLEEP (1)Insomnia (2)Sleepwalking (3)Narcolepsy.

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Presentation on theme: "Biological Rhythms and Sleep DISORDERS OF SLEEP (1)Insomnia (2)Sleepwalking (3)Narcolepsy."— Presentation transcript:

1 Biological Rhythms and Sleep DISORDERS OF SLEEP (1)Insomnia (2)Sleepwalking (3)Narcolepsy

2 Syllabus Biological Rhythms Circadian, infradian, and ultradian rhthyms, including the role of endogenous pacemakers and of exogenous zeitgebers in the control of circadian rhythms Disruption of biological rhythms, for example shift work, jet lag Sleep The nature of sleep including stages of sleep and lifespan changes in sleep Functions of sleep, including evolutionary and restoration explanations Disorders of Sleep Explanations for sleep disorders, including insomnia, sleep walking and narcolepsy

3 You must be able to… You MUST be able to Briefly outline each disorder DISCUSS at least one explanation for each disorder NB. All explanations revolve around biological and psychodynamic theories so USE THE SAME EVALUATION POINTS (but apply them appropriately)

4 Look, you know this stuff… Three disorders – Insomnia, Sleep Walking, Narcolepsy Biological – Genetic – Higher concordance for the disorders across MZ twins suggests a genetic component Biological – Neural (SCN, Pineal Gland, Melatonin, Hypocretin) – Insomnia and Narcolepsy – when the endogenous aspects which influence sleep/wake are abnormal – Sleep Walking – Underdeveloped / abnormal neural structures which influence sleep, especially those which lead to paralysis Psychodynamic – Early trauma -> Unconscious Conflicts -> abnormal behaviours to overcome / escape from / revert to a time before trauma

5 Discuss explanations for INSOMNIA (8+16) What is Insomnia – A common dyssomnia – Different durations (Transient, Short Term, Chronic) – Different Types: PRIMARY vs SECONDARY

6 Discuss explanations for INSOMNIA (8+16) DESYNCHRONISATION Insomnia a result of EPs becoming desynchronised with new EZs EVALUATION – Can only explain transient and short term insomnia as EPs will resynchronise after a few days – Doesn’t take into account individual differences; some people do not experience insomnia when experiencing new EZs PERSONALITY FACTORS People with a Neurotic Personality are likely to suffer from insomnia – Paranoia, excessive thoughts, etc EVALUATION – Incomplete

7 Discuss explanations for INSOMNIA (8+16) BIOLOGICAL FACTORS Hyperarousal – Brain scans of Insomniacs show increased neural activity in the hypothalamus and PFC. Makes sense as these areas contain key structures which influence sleep. Abnormal SCN - does not instruct the pineal gland to produce MELATONIN therefore a person will not fall asleep Abnormal brain chemistry – Post mortums of insomniacs indicate a reduction of GABA / GABA receptors. Makes sense as GABA is an inhibitory neurotransmitter [GABA especially inhibits motor activity] so low levels will lead to an inability to ‘switch off’ Genetic Abnormalities – some evidence for genetics – Beaulieu-Bonneau – 35% of insomniacs had a first degree relative who suffered the disorder – Watson – 0.47 concordance for insomnia across MZ twins, 0.15 between DZ twins). – NB. Never 100% concordance; indicates that environmental factors must be involved

8 Discuss explanations for INSOMNIA (8+16) BIOLOGICAL FACTORS – Evaluation OBJECTIVE, TESTABLE, FALSIFIABLE – EVIDENCE, But METHODOLOGICAL ISSUES with evidence – Correlational nature – Problems with post mortems OVERLY DETERMINISTIC AND INCOMPLETE; – There are insomniacs who do not posses any of the biological abnormalities specified previously but who still suffer from the disorder – need to take into account other factors (e.g. personality traits such as neuroticism) and take an IDIOGRAPHIC approach – Diathesis – Stress? CAUSE AND EFFECT ISSUES – Insomnia may be an effect of an underlying disorder (e.g. sleep apnoea). Important to take this into account as there are major treatment implications

9 Discuss explanations for SLEEP WALKING (8+16) What is SLEEP WALKING? – A PARASOMNIA – Does not result in day time sleepiness – Sleep walkers can carry out many, sometimes complicated, tasks (e.g. driving a car)

10 Discuss explanations for SLEEP WALKING (8+16) PSYCHODYNAMIC explanation SW is an expression of unresolved unconscious conflicts SW is when a person ‘acts out’ repressed traumas and anxieties, which ‘spill into’ NREM May represent a desire to sleep where a person slept as a child; sleepwalker is trying to ‘get back’ to a place associated with low anxiety EVALUATION UNFALSIFIABLE and based on ABSTRACT CONCEPTS – Making it unscientific and difficult to test / prove SUBJECTIVE INCOMPLETE

11 Discuss explanations for SLEEP WALKING (8+16) BIOLOGICAL NEURAL – Post Mortems of Sleep Walkers show underdeveloped neural mechanisms, especially those which inhibit movement during sleep (e.g. GABA structures underdeveloped / abnormal as these inhibit motor movements [sleep paralysis]) – Explains why sleepwalking is most common in children GENETIC – Some evidence for role of genetics (higher concordance between MZ twins than DZ twins – Bakwin), especially abnormality of the HLA Gene (BASSETTI -50% of SW had a HLA abormality) – But not 100% so environmental factors must be involved EVALUATION OBJECTIVE, TESTABLE and FALSIFIABLE HYPOTHESES Problems with research OVERLY DETERMINISTIC and INCOMPLETE TOO SIMPLISTIC: – DIATHESIS – STRESS approach the most complete explanation…

12 Discuss explanations for NARCOLEPSY (8+16) What is NARCOLEPSY? – A DYSSOMNIA – Rare: 1 in 2000 – May be accompanied by CATAPLEXY (loss of muscle tone), HYPNOGOGIC HALLUCINATIONS (dreamlike experiences), SLEEP PARALYSIS

13 Discuss explanations for NARCOLEPSY (8+16) GENETIC Narcolepsy may be caused by inherited genetic abnormalities Evidence from SELECTIVE BREEDING studies with DOGS Lin = Chromosome 12? Makes sense as this is responsible for regulating HYPOCRETIN (which regulates arousal and wakefulness) EVALUATION EXTRAPOLATION ISSUES (the genetic abnormality seen in the dogs does not apply to humans) INCOMPLETE – narcolepsy DOES NOT APPEAR TO RUN IN FAMILIES! Other factors must be more influential

14 Discuss explanations for NARCOLEPSY (8+16) NEURAL Narcolepsy caused by abnormalities with the structure / function of the hypothalamus Makes sense as the hypothalamus contains key sleep structures such as the SCN In narcoleptics, the SCN may be instructing the pineal gland to produce melatonin at random times, thus making the person uncontrollably fall asleep Also hypothalamus regulates HYPOCRETIN (see previous slide) and GABA production [which inhibits motor movement – explains the cataplexy associated with narcolepsy] EVALUATION EVIDENCE – Post mortem studies show narcoleptics had low levels of hypocretin producing cells But there are CAUSE AND EFFECT ISSUES with this research However, further support is offered by observation of DRUG use (e.g. amphetamines found to reduce narcolepsy and these influence hypocretin) DETERMINISTIC and INCOMPLETE TOO SIMPLISTIC - INTERACTIONIST approach the most complete

15 Discuss explanations for NARCOLEPSY (8+16) PSYCHODYNAMIC Narcolepsy is a defence mechanism employed by the Ego to allow a person an escape from trauma and anxiety Makes sense as narcolepsy is often triggered in high anxiety / emotion causing situations Maladaptive EGO may stem from early trauma EVALUATION ABSTRACT and UNFALSIFIABLE TOO SIMPLISTIC – ignores the role of biological factors INCOMPLETE INTERACTIONIST THEORY the most complete?

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