Chapter 14: Treatments for Anxiety Disorders
The DSM-IV classifies anxiety disorders as 1) panic disorders, 2) specific
phobias, 3) social phobias, 4) obsessive-compulsive disorders, 5) post-traumatic
stress disorders, and 6) generalized anxiety disorders.
Many individuals with anxiety disorders also have agoraphobia, a profound fear
of being in a situation from which escape is difficult or embarrassing, particularly
if a panic attack occurs.
Panic attack, which is the primary feature of panic disorders, is strong
physiological fear associated with intense apprehension, fearfulness, or terror.
o Often mistaken for a heart attack the first time it occurs.
Specific phobias consist of significant anxiety provoked by exposure to a specific
feared object or situation.
o Fear of heights (acrophobia) or spiders (arachnophobia) and less common
fears such as fear of clown (coulrophobia)
o Depending on the type, a phobia may cause significant disruptions in
normal daily living activities.
Social phobia, also referred to as social anxiety disorder, is a fear of being in or
performing in social or public situations. These situations provoke an immediate
anxiety response, one that may be severe enough to elicit a panic attack.
Obsessive-compulsive disorder (OCD) consists of anxiety arising over
obsession and compulsive behaviour that endeavors to reduce this anxiety.
o Common obsessions include thoughts about germs or other
contaminations, unresolved doubts (such as whether doors have been left
open or home appliances have been left on), and not having objects in
precise order (Monica from Friends).
o Because of these anxiety-causing obsessions, individuals with OCD
engage in compulsive behaviours that reduce this anxiety.
Post-traumatic stress disorder (PTSD) is characterized by a persistent state of
physiological arousal or exaggerated response to certain stimuli, particularly those
associated with a traumatic event.
Generalized anxiety disorder is characterized by excessive worry about events,
individuals or activities. Individuals with generalized anxiety disorder may
constantly feel worried and subsequently exhausted.
Genetics accounts for 47% of the likelihood of developing PTSD after
experiencing a traumatic event.
The Amygdala’s Role in Anxiety
In humans, increased activity in the amygdala causes states of fear and anxiety,
and amygdala dysfunction occurs in every type of anxiety disorder with the
possible exception of OCD.
Rather, researchers associate OCD with abnormal functioning in the thalamus,
cingulate cortex, prefrontal cortex, orbitofrontal cortex, basal ganglia, and nucleus
accumbens. Increased amygdala activity during fear conditioning, in which a stimulus is
associated with an aversive event such as a shock
Increases in amygdala activity occur when receiving oral warnings, watching
videos of humans being fear conditioned, and seeing faces with frightened
The amygdala receives information from many parts of the brain. The nervous
system sends sensory information including visual, auditory, touch, and pain from
thalamus to the amygdala via two pathways.
o First, the thalamo-amygdala pathway sends crude and unprocessed sensory
information directly from the thalamaus to the amygdala (short route).
This provides only basic features of the stimulus, such as loud noise, but
does not indicate what the stimulus actually is.
o Second, the thalamo-cortical-amygdala pathway sends sensory
information to the amygdala after processing in the cerebral cortex (long
route). For example, instead of loud noise as the short pathway may
communicate, a person may afterward discern a dog’s park as the long
pathway may communicate
The hippocampus sends information on the context surrounding stimulus to the
amygdala. Thus, if the context of the environment is important for the amygdala’s
response to the stimulus, then information sent from the hippocampus will modify
o A person may have a weak fear response when seeing a large dog behind a
Inputs to the amygdala from the prefrontal cortex act to reduce amygdala activity,
resulting in an inhibited reaction to fearful stimuli. Also important for extinction
of fear conditioning.
Anxious Feelings, the Amygdala, and the Sympathetic Nervous System
Just as the amygdala receives fear-related stimuli, the amygdala also sends
information for fear-related responses.
After receiving fear-related stimuli, the amygdala sends output signals to the
prefrontal cortex, hypothalamus, and locus coeruleus, among other structures.
The prefrontal cortex determines how we behave in a fearful situation—that is,
whether we should approach or avoid a fearful stimulus.
The hypothalamus and locus coeruleus facilitate physiological reactions to fear.
Signals from the amygdala and the hypothalamus travel to the locus coeruleus,
and the locus coeruleus ultimately causes the release of acetylcholine from
preganglionic nerves in the sympathetic nervous system.
This in turn causes the release of epinephrine (adrenaline) and noreprinephrine
from the adrenal gland. If the sympathetic nervous system is active enough then
respiration, heartbeat, blood pressure, and sweating increase.
Panic attacks can be experimentally indeuced through hyperventilation or
exposure to CO2 gas.
Stress and the HPA Axis General adaptation syndrome: stress syndrome occurring in three progressive
phases: alarm stage, resistance, and exhaustion.
Second stage: hypothalamic-pituitary-adrenal (HPA) axis – a system involved
in physiological responses to stress.
Prolonged increases in cortisol levels are associated with damage to the
hippocampus, an important structure for cognition and a site of action for
serotonin reuptake inhibitors, which are used for the treatment of anxiety and
For these reasons, researchers consider cortisol a stress hormone and have heavily
studied its potential role in disorders associated with prolonged stress such as
When referring to changes in hormone or neurochemical levels, researchers often
categorize these changes in two phases.
A tonic phase is generally a baseline state; for PTSD, this might be altered
cortisol levels before a traumatic event or altered cortisol levels during a normal
day after being diagnosed with PTSD.
A phasic phase occurs during a stressful event, which for PTSD might have been
the actual traumatic event that led to PTSD or the presence of stimuli that might
trigger reminders about the traumatic event.
Anxiolytic and Antidepressant Drugs and the Treatment of Anxiety
Drugs prescribed to treat anxiety are called anxiolytic drugs.
Barbiturates were commonly used in psychiatric hospitals and prescribed by
general family physicians for sleep, nervousness, and other purposes.
Long acting barbiturates generally take at least 1 hour to take effect, but produce
these effects for 10-12 hours. Have poor lipid solubility and slow metabolism.
Ultrashort-acting barbiturates produce effects within 10-20 seconds and maintain
drug effects for approximately 30 minutes. These barbiturates are highly soluble
in lipids, quickly store in fats, and rapidly metabolize.
Other uses for barbiturates include anesthesia and reduced seizur