chapter 17 anxiety disorders, autistic disorder, attention

Chapter 17

Anxiety Disorders, Autistic Disorder, Attention-Deficit/Hyperactivity Disorder,

and Stress Disorder

Anxiety Disorders Panic Disorder

Anxiety disorder:• A psychological disorder characterized by

unrealistic fear and anxiety.1. Panic disorder

2. obsessive compulsive behavior Panic Disorder:

• A disorder characterized by episodes of intense fear accompanied by symptoms such as shortness of breath and irregularities in heartbeat.

Copyright © 2004 Allyn and Bacon

Anxiety Disorders Panic Disorder

Anticipatory anxiety:• A fear of having a panic attack; may lead to the

development of agoraphobia.

Agoraphobia:• An unrealistic and intense fear of being away

from home or other protected places.• In severe cases people will not leave home!

Anxiety Disorders

Panic DisorderPossible Causes:

Genetic origins:• Evidence supports some anxiety disorders may

be inherited.Associated with joint hypermobility.

Neurotransmitters:• Serotonin and central benzodiazepine receptors

may be involved in anxiety disorders.• Treated with benzodiazepines and occasionally

SSRIs Brain Structures:

• Imaging studies suggest that the cingulate gyrus, prefrontal, and anterior temporal cortices are involved in panic attack.

Anxiety Disorders Obsessive-Compulsive Disorder

Obsessive-compulsive disorder:• A mental disorder characterized by obsessions

and compulsions.

Obsession:• An unwanted thought or idea with which a person

is preoccupied.

Compulsion:• The feeling that one is obliged to perform a

behavior, even if one prefers not to do so.

Anxiety Disorders

Examples of obsessions: Concern for order Cleanliness, germs Forbidden sexual thoughts

Examples of compulsions: Hand washing Checking Collecting Repeating behaviors (in and out of a door)

Anxiety Disorders Obsessive-Compulsive Disorder Possible Causes:

Genetic Origin:• Evidence is beginning to accumulate suggesting

that OCD might have a genetic origin. Family studies:

• Some research suggests OCD is associated with Tourette’s; a neurological disorder that appears during childhood.

Treatment:

• SSRIs , tricyclic antidepressants (desipramine,

clomipramine)

Copyright © 2004 Allyn and Bacon

Anxiety Disorders Obsessive-Compulsive Disorder Possible Causes:

Tourette’s syndrome:• A neurological disorder characterized by tics and

involuntary vocalizations and sometimes by compulsive uttering of obscenities and repetition of the utterances of others.

• Treatment with antipsycolics (dopamine antagonists, D2)

Anxiety Disorders Obsessive-Compulsive Disorder Possible Causes:

Cingulotomy:• The surgical destruction of the cingulum bundle,

which connects the prefrontal cortex with the limbic system; helps to reduce intense anxiety and the symptoms of obsessive-compulsive disorder.

• Only used on patients who are unresponsive to drug treatment.

Autistic Disorder Description:

Autistic Disorder:• A chronic disorder whose symptoms include

failure to develop normal social relations with other people, impaired development of communicative ability, lack of imaginative ability, and repetitive, stereotypical movements.

Autistic Disorder Possible Causes:

Biological:

• Research and mental health professionals are

convinced autism is caused by biological factors.

• Between 2 and 3 percent of siblings of people

with autism are themselves autistic.

• There is a 70 percent concordance rate for

monozygotic twins.

Copyright © 2004 Allyn and Bacon

Autistic Disorder Possible Causes:

Phenylketonuria (PKU):

• A hereditary disorder caused by the absence of

an enzyme that converts the amino acid

phenylalanine to tyrosine; causes brain damage

unless a special diet is implemented soon after

birth.

Autistic Disorder Possible Causes:

Brain pathology:

• Heritable aspect of autism suggests the disorder

is a result of structural or biochemical

abnormalities in the brain.

• Researchers have found evidence for structural

abnormalities in the brains of autistics, but so far

we cannot point to any single abnormality as the

cause of the disorder.

Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD):

• The principal characteristics of ADHD are

inattention, hyperactivity, and impulsivity.

These symptoms appear early in a child's life.

• There are three patterns of behavior that indicate

ADHD. People with ADHD may show several

signs of being consistently inattentive. They may

have a pattern of being hyperactive and

impulsive. Or, they may show all three types of

behavior.

Attention-Deficit/Hyperactivity Disorder

Inattention

• Often becoming easily distracted by irrelevant sights and sounds (hyper vigilant)

• Often failing to pay attention to details and making careless mistakes

• Rarely following instructions carefully and completely losing or forgetting things like toys, or pencils, books, and tools needed for a task

• Often skipping from one uncompleted activity to another.

Attention-Deficit/Hyperactivity Disorder

Hyperactivity-Impulsivity

• Feeling restless, often fidgeting with hands or feet, or squirming while seated

• Running, climbing, or leaving a seat in situations where sitting or quiet behavior is expected (lack of impulse control)

• Blurting out answers before hearing the whole question (lack of impulse control)

• Having difficulty waiting in line or taking turns.

Attention-Deficit/Hyperactivity Disorder

Possible causes

• There is strong evidence from family and twin studies for hereditary

factors in a person’s likelihood of developing ADHD.

• Thirty-six percent of all findings were positive (P< 0.05), 17% were

trends (0.05 <P < 0.15), and 47% were negative (P > 0.15).

• Genetic investigations have supported the role of both dopamine D4

receptor gene (DRD4) and dopamine transporter gene (DAT1) in the

vulnerability to the disorder.

• The DRD4 gene has been postulated as a candidate gene for

attention-deficit-hyperactivity disorder

Lower DA binding in basal ganglia

Increased DA transport in frontal lobes

Attention-Deficit/Hyperactivity Disorder

Other causes Possible correlation between the use of cigarettes

and alcohol during pregnancy. Lead paints? Sugar sensitivities? Head injuries?

Attention-Deficit/Hyperactivity Disorder

Brain structure involvement:

• Studies of brain structure of people with ADHD

do not reveal any localized abnormalities,

though the total volume of their brains is

approximately 4% smaller than normal.

• Candidates:

Frontal lobes

Medial temporal lobes

Caudate nucleus

Attention-Deficit/Hyperactivity Disorder

NIMH Child Psychiatry Branch studied 152 boys and girls with ADHD, matched with 139 age- and gender-matched controls without ADHD. The children were scanned at least twice, some as many as four times over a decade. As a group, the ADHD children showed 3-4 percent smaller brain volumes in all regions—the frontal lobes, temporal gray matter, caudate nucleus, and cerebellum.

Attention-Deficit/Hyperactivity Disorder

The Reticular Activating System

• Decreased NE activity in RAS• Poor attention, learning difficulties, memory deficits, lack

of behavior control• Treatment with amphetamines increase RAS activity

• Increased RAS activity• Hyperactivity, restlessness, hyper vigilant• Treatment may include Clonadine (NA Antagonist)

Attention-Deficit/Hyperactivity Disorder Drug Treatment

• Adderall amphetamine• Concerta methylphenidate• Cylert pemoline*• Dexedrine dextro-amphetamine• Ritalin methylphenidate

* DA agonist? Mechanism not well described

Stress Disorders

Stress:

• A pattern of physiology common to all stressors

Stressor:

• A stimulus (or situation) that produces a

generalized stress response.

Stress Disorders

Fight-or-flight response:

• First stage of the stress response where

organism is mobilized.

• Changes in hormonal and sympathetic activity in

preparation for response.

Stress Disorders Physiology of Stress

Glucocorticoid (cortisol)

• One steroid hormone of the adrenal cortex that is

important in protein and carbohydrate

metabolism, secreted especially in times of

stress.

Stress Disorders Physiology of Stress

Corticotropin-releasing hormone (CRH):

• A hypothalamic hormone that stimulates the

anterior pituitary gland to secrete ACTH.

Adrenocorticotropic hormone (ACTH):

• A hormone released by the anterior pituitary

gland in response to CRH; stimulates the adrenal

cortex to produce glucocorticoids.

Copyright © 2004 Allyn and Bacon

Copyright © 2004 Allyn and Bacon

Stress Disorders Psychoneuroimmunology

Psychoneuroimmunology:• The branch of neuroscience involved with

interactions between environmental stimuli, the nervous system, and the immune system.

Antigen:• A protein present on a microorganism that

permits the immune system to recognize the microorganism as an invader.

Stress Disorders Psychoneuroimmunology

Antibody:• A protein produced by a cell of the immune

system that recognizes antigens present on invading microorganisms.

B-lymphocyte:• A white blood cell that originates in the bone

marrow; part of the immune system.

Stress Disorders Psychoneuroimmunology

Immunoglobulin:• An antibody released by B-lymphocytes that bind

with antigens and help to destroy invading microorganisms.

T-lymphocytes:• A white blood cell that originates in the thymus

gland; part of the immune system.

Stress Disorders Psychoneuroimmunology

Cytokine:• A category of chemicals released by certain white

blood cells when they detect the presence of an invading microorganism; causes other white blood cells to proliferate and mount an attack against the invader.