Ch.18 Anxiety Disorder, Autistic Disorder, and Stress Disorders
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Transcript of Ch.18 Anxiety Disorder, Autistic Disorder, and Stress Disorders
Copyright 2001 by Allyn & Bacon
Carlson (7e) PowerPoint Lecture Outline Chapter 18: Anxiety Disorder, Autistic Disorder and Stress
Disorders
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Copyright 2001 by Allyn & Bacon
Anxiety Disorders
The common element of the anxiety disorders is the presence of unrealistic, unfounded anxiety
Panic disorder involves episodes of intense anxiety
Obsessive-compulsive (O-C) disorder refers to anxiety associated with recurrent thoughts and actions
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Copyright 2001 by Allyn & Bacon
Panic Disorder (PD)
Physical symptoms of panic disorder include Shortness of breath and irregular heartbeat Dizziness and feelings of unreality
Episodes of panic occur in 1-2 % of population Panic disorder has an early onset (rare after age 35)
Symptoms of PD are similar across cultures Anticipatory anxiety about future panic attacks
leads to Agoraphobia: fear of panic attack in public places
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Copyright 2001 by Allyn & Bacon
Biological Bases of PD
MZ twins have a higher concordance rate for panic disorder than do DZ twins
Panic Disorder is more likely in families of patients with the disorder Family pattern of panic disorder suggests that PD is caused by a
single dominant gene Panic attacks can be triggered by events that activate the
autonomic nervous system: Lactic acid injections Caffeine consumption Breathing air containing high levels of carbon dioxide
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Copyright 2001 by Allyn & Bacon
Anxiety may involve Reduced levels of benzodiazepine receptors and
lowered sensitivity to an unknown endogenous benzodiazepine agonist
CCK-4, a peptide that induces panic attack in PD patients, but not in normal subjects
Reduced serotonin activity in brain The serotonin agonist fluoxetine can be be used to treat PD Yet, the tryptophan depletion procedure, which reinstates
depression, does not produce anxiety attacks in PD patients Altered activity within the frontal cortex
18.5
Copyright 2001 by Allyn & Bacon
Obsessive-Compulsive Disorder
Obsessions are recurrent thoughts Compulsions are recurrent behaviors
The incidence of O-C disorder (OCD) is 1-2 percent OCD begins in young adulthood Symptoms of OCD are similar across differing
cultures OCD can greatly limit life options
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Copyright 2001 by Allyn & Bacon
Compulsions
The four categories of compulsions include Counting (“am I missing a dollar?”) Cleaning (hands, house) Checking (“Did I turn the stove off?”) Avoidance (e.g. dirt)
Compulsions may represent exaggerations of normal species-typical behaviors aimed at keeping an animal clean and away from danger
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Copyright 2001 by Allyn & Bacon
Brain Activity and OCD
OCD is linked with a neurological syndrome Tourette’s syndrome involves
Muscular/vocal tics, facial grimaces, word repetition
OCD may involve damage to basal ganglia, cingulate gyrus, and prefrontal cortex OCD is associated with neurological syndromes that involve
damage to the basal ganglia (Huntington’s chorea) OCD is associated with increased activity within the frontal
lobes Drug therapy for OCD reduces frontal lobe activity Surgical transection of the subcortical frontal lobe leads to
improvement in OCD (as did a gunshot wound to the head)18.8
Copyright 2001 by Allyn & Bacon
Pharmacotherapy of OCD
Drug therapy for OCD involves drugs that are agonists for brain serotonin systems Blockade of 5-HT reuptake improves OCD symptoms
Clomipramine Fluoxetine Fluvoxamine
OCD drugs require weeks to relieve OCD symptoms Antagonism of 5-HT receptors worsens OCD, whereas the
tryptophan-depletion procedure does not 5-HT agonism appears to reduce intensity of the species-
typical behaviors (e.g. washing)
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Copyright 2001 by Allyn & Bacon
Serotonin and Compulsions
Human compulsions Trichtillomania refers to compulsive hair pulling Onychophagia refers to compulsive nail biting Both compulsions are reduced by ingestion of
clomipramine (a serotonin agonist) Dog compulsions
Acral lick dermatitis refers to compulsive licking by a dog of a body part; ALD is treated by administration of clomipramine
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Copyright 2001 by Allyn & Bacon
Autism
Autism involves self-absorption Specific features of autism include
Impaired social relations with others An inability to communicate
Literal interpretation of speech Impaired imaginative ability Stereotyped movements
Incidence of autism is 4/10,000 Males are 3 times more likely to develop autism
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Copyright 2001 by Allyn & Bacon
Biological Bases of Autism
Heritability of autism MZ twins exhibit a 96% concordance rate for autism, while that of
DZ twins is comparable to that of normal siblings 2-3% of the siblings of autistic children are themselves autistic
Autism is associated with neurological disorders: Phenylketonuria (PKU) Tourette’s syndrome
Factors that impair development lead to autism: Rubella, hydroencephalus Drugs such as thalidomide (exposure during prenatal days 20-24
impairs development of the brain stem)
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Copyright 2001 by Allyn & Bacon
Stress
Aversive stimuli can elicit emotional responses: Behavioral component: “Fight or Flight” response Autonomic component: Sympathetic activation Endocrine: secretion of epinephrine, norepinephrine
Physiological reactions to chronic aversive stimuli/situations can be damaging Stressors: the aversive stimuli we encounter Stress Response: our reaction to stressors
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Copyright 2001 by Allyn & Bacon
Hormone Secretion during Stress
Stressors evoke activity in the sympathetic nervous system
Adrenal glands release Epinephrine: biases energy flow to muscles, blood flow from
heart, and increases blood pressure Norepinephrine: is released in brain during stress Glucocorticoids: break down protein and fats to glucose,
increase blood flow, and stimulate behavioral responsiveness Cortisol secretion is controlled by a releasing factor (CRF)
produced by the PVN PVN CRF --> pituitary ACTH --> adrenals: secrete glucocorticoids CRF may act as a “stress” transmitter
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Glucocorticoid Secretion
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Chronic Exposure to Stressors
Chronic stress is damaging to health Air traffic controllers are more likely to develop
High blood pressure Ulcers and diabetes
Chronic secretion of glucocorticoids leads to: Increased blood pressure (--> stroke, heart attacks) Loss of neurons in brain (e.g. hippocampal field CA1) Suppression of the immune system (--> illness) Suppression of the inflammatory system (delays wound
healing)
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Posttraumatic Stress Disorder
Posttraumatic Stress Disorder (PTSD): Acute exposure to very intense stressors (air
disasters, war, assault) can have delayed stress effects
Dreams, recall of trauma event Flashback episodes of event Intense distress
PTSD symptoms include: Diminished social interests Suppressed emotional feelings Feelings of detachment
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Predisposing Factors for PTSD
Personality variables that predispose to PTSD: Tendency to brood about feelings
Vietnam Veterans study identified four factors that contribute to developing PTSD Family financial difficulty History of drug abuse/dependence History of affective disorders History of childhood behavior problems
PTSD patients exhibit reduced volume of the hippocampus (consistent with toxic action of glucocorticoids on hippocampal cells)
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Coping Responses and Stress
Stress reflects our reaction to stressors Coping implies modifying our responses:
Exerting control over aversive stimuli can reduce stress responses
Weiss study: rats that avoid shock show fewer ulcers
Coping may involve an increase in the level of benzodiazepines in brain (would act via GABAA sites to reduce anxiety)
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Copyright 2001 by Allyn & Bacon
Psychoneuroimmunology
Psychoneuroimmunology is the study of the interactions between the immune system and behavior Stress responses can impair the immune system Leading to illness and potential death
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Overview of the Immune System
Immune system acts to destroy foreign organisms (viruses, bacteria, fungi)
Nonspecific reactions: act to destroy organisms or infected cells Inflammatory reaction: damaged cells leak substances that
increase blood flow Phagocytotic white blood cells: destroy damaged cells Cell infection --> interferon secretion (reduces viral
replication) Natural killer cells: detect and destroy infected cells
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Immune Reactions
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Chemically-Mediated Cell-Mediated
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Specific Immune Reactions
Specific immune reactions include: Chemically-mediated: immune system produces
antibodies that recognize the antigens present on surface of a foreign cell
B-lymphocytes: produce immunoglobulin antibodies that destroy foreign cells
Cell-mediated: antibodies on exterior of T-lymphocytes detect foreign antigens (viruses)
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Copyright 2001 by Allyn & Bacon
Stress and the Immune Response
Stress increases the likelihood of infectious disease Students are more likely to be ill during exam times Death of a spouse leads to illness of survivor
Explanation: stress releases glucocorticoids that in turn impair the immune system
Supporting Evidence: Bereavement leads to reduced immune response Alzheimer’s caregivers have impaired immune response Inescapable shock in rats reduces T-cells, B-cells and natural
killer cells
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