Anxiety Disorders 11/21/2012 11:29:00 AM
Anxiety Disorders
Class of disorders distinguished by feelings of excessive apprehension, anxiety, or fear
o Panic Disorder, Agoraphobia and Social Anxiety Disorder
o Generalized Anxiety Disorder
o Phobic Disorder
o Obsessive-Compulsive Disorder (OCD)
o Post-Traumatic Stress Disorder (PTSD)
Must cause significant distress or impairment of social occupational functioning
Can’t be caused by a substance
Panic Disorder
Discreet (clear beginning and clear end), recurrent, sudden and unexpected (no well-defined
stimulus) attacks of overwhelming anxiety
o Tachycardia (elevated heart rate, 100 beats/minute+), palpitations or chest pain
o Sweating
o Trembling or shaking
o Hyperventilation, shortness of breath, or smothering
Nausea or dizziness
Numbness or tingling
o Feelings of choking
o Derealization or depersonalization
o Fear of losing control or of dying
Apprehensive about being in public
Agoraphobia and Social Anxiety Disorder (Types of Panic Attacks)
Agoraphobia: fear of places or situations where escape would be difficult or embarrassing (in
the event of a panic attack)
o Fear of “marketplace”: outside of home, crowds
o Prisoner in own home
o Will venture outside with a confidante
Social Anxiety Disorder: persistent fear of one or more social performance situations
o Exposed to unfamiliar people or potential scrutiny by others
o Specific social situation(s) or most situations (generalized)
o Avoids situation that invariably provokes anxiety
o Recognizes that fear is excessive Phobic Disorder
Persistent and irrational fear of an object or situation; imagination is sufficient to provoke
anxiety
o Acrophobia (fear of height)
o Claustrophobia (fear of enclosed spaces)
o Hydrophobia (fear of water)
o Animal and insect phobias
Preparedness: prepared by evolution to acquire some fears more readily than others
o Snakes and spiders vs. cars and electrical outlets
One of the most common and least treated anxiety disorders
Generalized Anxiety Disorder
Chronic, high level anxiety tied to no specific threat
o Restlessness or insomnia
o Easily fatigued
o Difficulty concentrating
o Irritability
o Muscle tension
o Worry constantly about everything
o Avoid decisions and brood endlessly
o Always elevated
Anxiety is less intense compared to panic attack of phobia
Onset is gradual
Obsessive-Compulsive Disorder
Obsessions: persistent, uncontrollable intrusions of unwanted thoughts that produce anxiety
o Often reflect real dangers (contamination; security; safety) but not always
(symmetry)
Compulsions: urges to engage in ritual behavior (rigid set of repetitive behaviors or mental
acts) that relieves anxiety
o Often related to obsession (e.g. cleanliness; checking; counting and organizing)
Recognizes obsessions/compulsions are unreasonable
Onset before age 35
Heterogeneous disorder
o Checking: concerned with safety or security
o Symmetry and order: concerned with being equal on both sides, organization o Cleanliness and washing: clean a lot
o Hoarding: can’t throw anything away, shopping addictions
Post-Traumatic Stress Disorder
Elicited by experience with traumatic event
o Direct experience (rape, assault, combat)
o Witnessing a traumatic event (murder)
o Witnessing the aftermath of traumatic event (natural disaster)
Onset can be delayed months or years after event
Event is re-experienced: flashbacks (involuntary) or nightmares; feed as thought he event
were recurring
Avoidance of cues to event and numbing of general responsiveness
o Avoidance of thoughts or activities associated with event
o Inability to recall important aspects of event
o Diminished interest or participation in important activities
Person loses interest in their own lives
o Restricted affect or estrangement from others
Increased arousal
o Insomnia
o Irritability
o Difficulty concentrating
o Hypervigilance: tend to monitor their environments more than average
o Exaggerated startle response
Acute (less than 3 months) vs. chronic (longer than 3 months)
Epidemiology
Prevalence for anxiety disorders
o Lifetime prevalence – 30%
o One year prevalence – 12%
o Ratio of women to men – 2:1
o Cultural variability
Anxiety disorder – 12 month prevalence
o Specific phobia – 6.2-8.0%
o Social phobia – 6.7%
o OCD – 1.8%
o Generalized anxiety – 1.1% o Panic disorder – 0.7%
Onset usually in early adolescence/adulthood
Peaks at age 30
PTSD: situation dependent
o 60% of men and 50% of women experience traumatic event
o 5% of men and 10% of women lifetime prevalence
Risk Factors
Genetic risk factors
o Panic Disorder shares genetic risk with Agoraphobia and specific phobic disorders
o OCD shares genetic risk with Tourette’s syndrome and chronic tic (involuntary
movements) disorders
Motor tics: involuntary, repetitive, non-rhythmic physical movements
Phonic tics: involuntary utterances
Have both of them Tourette’s
o Generalized Anxiety Disorder (GAD) shares genetic risk with PTSD and Depression
GAD has lowest heritability
Environmental risk factors
o Early traumatization: emotional/sexual abuse, parental neglect, heightened anxiety in
parents (insecure attachment)
Pathophysiological Mechanisms
Neurotransmitter activity
o Serotonin activity depends on the receptor type
SSRI relieves anxiety
LSD heightens anxiety
o Norepinephrine: understimulation of alpha-adrenergic neurons: overstimulation of
beta-adrenergic neurons
Alpha-receptor agonists relieve anxiety
Beta-blockers relieve anxiety
o Decreased GABA activity
Benzodiazepines and alcohol (GABA agonists) relieve anxiety
GABA goes up nervous system activity goes down
Alcohol boosts GABA activity
Brain functioning: amygdala and reciprocal connections with orbitofrontal cortex and
hippocampus o Basal ganglia abnormalities in OCD
Disinhibition to select motor activities
o Reduced volume in hippocampus in PTSD
Chronic activation of HPA in PTSD
o Orbitofrontal cortex assesses stimulus goes to amygdala (let fear go or cancel it)
Oh, it’s a snake, oh, it’s a rubber snake, let’s cancel the fear response
Orbitofrontal cortex: evaluation of emotional stimuli and fear conditioning
Comorbidity
Depression and substance abuse
o Panic disorder: 50-70% have depression
o Comorbid cases more severe and onset is earlier
o Alcohol abuse and dependence – 30%
Risk of suicide increased by magnitude of 10
o Higher in comorbid cases
High rates of comorbidity
o Social anxiety, agoraphobia, and panic disorder
o PTSD and phobic disorder
o OCD and Parkinson’s, Huntington’s, Tourette’s and tic disorders (basal ganglia)
Outcome and Treatment
Outcome: typically chronic with incomplete remissions. Panic disorder and agoraphobia
typically decline in severity after 40 years
Psychopharmacological treatment
o Acute cases: benzodiazepines (GABA agonist)
o Antidepressants (serotonin or monoamine agonist)
o OCD: higher doses of antidepressants + low-dose antipsychotics (reduce obsessions
and compulsions)
o PTSD: mood stabilizers + antipsychotics (reduce intrusive thoughts)
Psychotherapy: cognitive behavioral therapy
Systematic Desensitization
Used to treat phobias and other anxiety disorders with counter-conditioning
o Anxiety response acquired through classical conditioning
o Goal is to replace anxiety response with relaxation
Four-step process o Anxiety hierarchy
o Deep muscle relaxation
o Imagine each item on anxiety hierarchy while remaining relaxed
o Confront real stimulus
Evolutionary Synthesis
Fear responses reflect persistent dangers encountered in the EEA; motivate adaptive
responses to threat (flight, immobility, submission, or aggression)
o Smoke-detector principle: low threshold for fear response due to asymmetry of costs
associated with perceptual errors (false negatives > false positives)
o Biological predisposition to fear evolutionary significant stimuli that pose threats to
fitness (predator, rival, embarrassment)
Not born afraid of snakes, but children observe adults fear snakes
o Conditioning and observational learning augment fear response (e.g. fear of snakes in
chimpanzees)
Anxiety disorders reflect exaggerated fear responses to cues of danger or threat (real or
imagined)
o Could be a real threat, but fear response is disproportionate
o Could be imaginary
Fear is an adaptive response; anxiety is maladaptive
Evolution of Human Fears
Common sources of fear with corresponding adaptive problem
o 5-6 months: crawling
Snakes (venoms)
Spiders (poison)
Heights (fall)
o Panic (predation rival): response to almost imminent death
o Agoraphobia (crowded places)
o 2 years
Small animal phobias (disease)
o Hypochondriasis (disease): general fear of disease
o 9-13 months
Separation Anxiety (vulnerability)
Stranger Anxiety (dangerous males)
o Fear of blood injury o Sex differences: women experience more intense anxiety; have unique fear (rape)
o Fears emerge when they are most needed (most likely to adversely affect fitness)
Fear Relevance and Attention
Fear relevant stimuli are attended to more quickly than fear neutral stimuli
o Task: identify if all objects from same category or if one object was discrepant
o Discrepant object was either threat relevant or threat neutral
o Fear relevant targets had either high or low evolutionary significance
o There conditions: photographs, drawings, perceptual similarities
Threat relevant stimuli detected faster than threat neutral stimuli regardless of evolutionary
significance
Emotional vs. attentional responses
Maratos, Mogg & Bradley
Rapid Serial Visualization Paradigm (RSVP) – present two stimuli in rapid succession
o First stimulus masks the second unless the second has strong emotional meaning
Evolutionary Synthesis
Early experiences lead to a mistrustful inner working model of the world as a dangerous place
o Insecurely attached infants more likely to develop anxiety disorders (loss, rejection,
neglect)
Early experiences sensitize the fear response
o Amygdalae more responsive to fearful stimuli in patients with PTSD and SAD
o Diminished communication with orbito-frontal cortex (emotional evaluation) and
hippocampus (memory)
o Novel but benign environments perceived as dangerous
Humans might be particularly susceptible (high prevalence rates)
o Humans are social, but physically vulnerable; selection for greater vigilance;
neuroanatomical structures involved in evaluating threat increased in size over
evolutionary time
o Human juveniles are vulnerable for an extended period; greater dependence on secure
attachment; hypervigilance could be adaptive response in the event of insecure
attachment
o Human capacity to anticipate future events, including future threats
o Modern environment poses few real threats; neurobiological response lacks
“training” to respond accurately o Threat come from inside and outside social group; threats to physical wellbeing and
status
o Anticipating future events is adaptive (e.g. conserving food)
o Strangers were ancestral environment were real threats; not really nowadays
Evolutionary Synthesis of Specific Disorders
Panic Disorder: lowered threshold leads to false suffocation alarm
o Symptoms: hyperventilation, shortness of breath, smothering
o Carbon dioxide inhalation can induce panic in vulnerable individuals
o Panic more likely to occur when pCO2 levels a
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