A baby monkey that is
raised in captivity has no fear of snakes. But if he is shown
a film in which another monkey appears frightened of a snake,
then snakes will immediately become terrifying for him as
well. It would thus seem that this fear is not innate, in
the strict sense, but
rather is learned, albeit very rapidly. Interestingly,
this rapid learning of fear does not occur with other objects,
such as flowers, which shows that there is still something
innate about this process.
Some of the things that humans are predisposed to be afraid
of (and that often become the target of phobias) include snakes,
spiders, birds of prey, dogs, reptiles, and heights. But our
evolutionary predispositions are of little help to us in dealing
with some very real modern-day dangers, such as firearms and
automobiles.
The studies showing that monkeys are predisposed to be afraid
of snakes point in the same direction: they confirm that the
mechanism by which phobias originate is very old and was established
even before hominization.
PHOBIAS
Phobias may be associated with a specific
object or situation,
but in either case, they seem to originate from a combination
of biological factors and certain events that have marked the
life of the individual concerned.
Some Freudian psychologists believe that phobias may sometimes
be caused by unconscious psychological conflicts. In contrast,
proponents of learning theory believe that the extreme fears associated
with phobias are simply learned, either directly (for example,
when someone is bitten by a snake) or indirectly (when someone
observes someone elses's reactions of fear or pain; see sidebar).
Often a phobia may also arise from a conditioned
fear, in which a neutral object that is present at the same time
as a threatening stimulus becomes associated with that stimulus
and thus itself gradually acquires connotations of danger. For
example, in the 1920s, researchers demonstrated that they could
condition a child to be afraid of a harmless laboratory rat if
they simply made the child hear an unpleasant noise whenever the
rat was nearby. This phenomenon may also explain the irrational
nature of some phobias—the fear-conditioning process often
occurs without the individual's being aware of it, so that he or
she would later have trouble in remembering the event that first
gave rise to this fear.
In other
people, however, a phobia may develop as the result of an identifiable
traumatic event. For example, if someone experiences a panic
attack in a broken elevator, it might result in a fear of any
enclosed space (claustrophobia).
Other kinds of phobias are more common within
particular families, which suggests that some genetic factors may
be at work. But the question is still open as to whether this higher
frequency is due to heredity or simply to having grown up around
other anxious people. For example, studies have shown that in general,
people who have social
phobia or agoraphobia have experienced a family breakdown,
felt shy, had few romantic relationships, and not been encouraged
by their parents to develop social ties.
Many of the explanations offered for the origins of phobias also
revolve around the idea that people have a biological predisposition to
be more sensitive to certain specific stimuli such as snakes, spiders,
and the dark, which is why these stimuli are the subject of phobias
throughout all cultures in the world.
Indeed,
phobias very commonly involve categories of objects or situations
that seem to have been especially significant in the course
of human evolution. In a
stable environment like the one that our ancestors lived in,
the dangers that threatened a species changed very slowly.
Hence a mechanism that let people quickly learn to recognize
such dangers could be very advantageous.
This evolutionary mechanism would explain
why phobias about electrical power lines are very rare, even though
these lines are very common and dangerous in modern society, while
phobias about many harmless insects are very common, simply because
they remind us of other insects that are potentially very dangerous.
PANIC DISORDERS
At least once in our lives, most of us
have suffered a panic attack brought on by some specific event.
But people who have panic disorders experience panic attacks
suddenly and with no apparent external threat that precipitates
them. These attacks peak rapidly, usually in less than 10 minutes,
and then subside. But despite their brevity, these attacks are
typically described by their victims as terrifying experiences
that leave them drained of emotion and anxious about their health.
The fear of having another attack becomes
so worrisome that these people quickly learn to avoid the situations
that seem to have triggered these episodes. Some people alter
their behaviour considerably, thus somewhat relieving their anxiety
about having more attacks. But some of the changes they make
are so radical that they can cause even more serious problems.
One such
problem is panic disorder with agoraphobia.
Contrary to what the Greek and Latin roots of this word suggest,
agoraphobia is the fear not only of open spaces but also
of any
situation that can cause anxiety. This anxiety is quite
often associated with the fear of losing control in places
where it could become embarrassing to do so. These places
may include not only open spaces such as public squares or
crowds, but also closed spaces such as supermarkets, buses,
and airplanes.
In fact, often these will be places where
the person has previously experienced a panic attack. The circumstances
that precipitated the original attack seem to give way to a lasting
association with any environment resembling the one where the
attack took place. Thenceforth, such an environment will generate
anxiety and possibly further panic attacks, thus potentially
creating a positive feedback loop that increases the number of
anxiety-producing situations and panic attacks even more.
Panic disorders occur
in about twice as many women as men and in all countries,
ethnic groups, and social classes. An estimated 33% of
the general population will suffer a panic attack each
year, but panic disorders are far rarer, affecting less
than 1% of the population.
Most panic attacks last only a very few minutes; some last
up to 10. They can occur for the first time at any age, but
most often do so in early adulthood. Studies have also shown
that they might be more common in certain families, which
suggests the possibility of a genetic component.
Other studies have shown that in people with panic disorders,
common antecedents include stressful events or the anticipation
of such events, anxiety in childhood, overprotective parents,
and substance abuse.
In predicting the seriousness
of cases of PTSD, the seriousness of the originating trauma
(such as the injuries suffered in a physical attack) may
be less important than the survivor's initial emotional reaction.
Certain people appear to be be more vulnerable to PTSD, in
particular people who have experienced depression, anxiety,
or other traumas in the past, or who are predisposed to anger,
or whose style of adapting to stress involves not talking and
not thinking about the traumatic event.
POST-TRAUMATIC
STRESS DISORDER (PSTD)
Post-traumatic stress disorder (PTSD) involves
severe anxiety resulting from stimuli to which someone was exposed
during a traumatic event. PTSD is common in combat veterans,
but the
same symptoms have been found in victims of sexual abuse,
physical trauma, highway and workplace accidents, and life-threatening
illnesses such as cancer, as well as in people who are repeatedly
exposed to other people's traumas, such as emergency-room nurses
and ambulance attendants. Some psychiatrists also speak of PTSD
in people who are especially troubled by the death of a close
friend or relative.
Like phobias, PTSD is regarded
by many authors as a particular form of conditioned fear. The
difference is that in PTSD, it is the unconditioned stimulus
that plays the decisive role, assuming the status of a genuinely
traumatic experience—one that differs significantly from
the kinds of events experienced in everyday life.
Many researchers
believe that PTSD results from adaptive mechanisms. For
example, symptoms
of hypervigilance may represent the body's attempts
to stay alert enough to do whatever is necessary to stay
out of danger. The deadening of emotions might represent
a mechanism that protects the individual when the stress
level is too high to handle. The problem with PTSD is that
these mechanisms remain active even when they are no longer
necessary, thus disturbing the individual's behaviour.
This condition of acute stress develops rapidly after
a traumatic event and lasts less than a month. PTSD will
not be diagnosed unless these disturbances persist for
more than a month and cause the individual profound distress.
Many other psychological
disorders can coexist with PTSD. For example, because people
who have PTSD are constantly reliving the traumatic event,
they often suffer from depression as well. They may also
be subject to panic attacks triggered by persons, places,
or conversations that remind them of the traumatic event.
Lastly, many people who have PTSD turn to drugs as a way
of coping with the painful memories associated with their
trauma. But in the long term, drugs will only accentuate
the symptoms of anxiety and depression.
The connection between
stress and OCD is not well understood, but researchers have
observed that 50 to 70% of people with OCD develop their
symptoms after some stressful event in their lives, such
as job loss or the death of a relative.
OBSESSIVE-COMPULSIVE
DISORDER (OCD)
Obsessive-compulsive disorder involves
thoughts and/or behaviours that are invasive, persistent, and
repetitive. These behaviours are carried out in a very precise
way that is meant to neutralize anxiety, but they constitute
such excessive responses to the situations that they are meant
to neutralize that they can actually become quite a handicap.
The exact causes of obsessive-compulsive
disorder (OCD) are not yet well understood. It was once thought
that a very strict upbringing, emotional deprivation, or
an excessive emphasis on cleanliness in childhood might contribute
to the development of OCD later in life. But these explanations
were soon found inadequate. In other words, you do not have
to have monsters for parents in order to develop OCD.
As with many other anxiety disorders, certain
genes may be involved in OCD. Cases of OCD that develop in childhood
tend to be hereditary. When a parent has OCD, there is a slightly
higher probability that his or her child will do so as well.
When OCD is inherited, it is the general nature of the disorder
that seems to be transmitted, and not the specific symptoms (for
example, a mother may have a handwashing compulsion, while her
child engages in compulsive checking rituals).
More recent studies also seem to indicate that streptococcal
infections in young children may damage the part of the brain
responsible for repetitive behaviour and thus predispose these
children to develop OCD. Other preliminary studies have found
that the brains of people who had OCD contained less white matter
than those of people who did not.
Brain-imaging studies have also revealed differences between
the brain-activity patterns of OCD sufferers and those of normal
subjects. For example, people with OCD seem to show a problem
in communication between the frontal cortex and the deeper structures
of the central grey nuclei. Positron-emission tomography (PET)
scans have also shown that after treatments that
produced notable improvements in the condition of OCD patients,
the activity patterns in these parts of the brain became more
normal.
Researchers have also found lower levels of serotonin in these
parts of the brain in OCD patients, which helps to explain why
treatment with selective
serotonin reuptake inhibitors (SSRIs) produces positive effects.
The compulsive, repetitive
behaviours of OCD develop slowly and insidiously and become
harder and harder to control. It is not unusual for some
OCD sufferers to take two or three showers or wash their
hands 100 times every day. Others may spend tremendous
amounts of time tidying their home according to very special
criteria, such as lining up all their canned foods in alphabetical
order and folding their clothes in a very precise way.
Still others may need to follow exactly the same path and
cross the streeet at exactly the same spot on their way
to work every day.
Some OCD patients are obsessed with numbers: they must brush
their hair exactly the same number of strokes every morning,
or wait the same number of rings every time before they answer
the telephone, or tap a table a certain number of times whenever
they pass by it.
OCD is diagnosed when such ritualized behaviours are causing
the person significant distress and taking up so much time
(in general, more than one hour per day) that they are interfering
with his or her normal daily activities.
Anxiety is a psychological
mechanism that can very likely serve useful purposes for
human beings. It is closely related to our ability to anticipate
and to project into the future. This ability to construct
mental scenarios is far more advanced in humans than in other
species whose
prefrontal cortex is less developed. Hence this faculty
is involved in many behaviours that make us uniquely human.
But when it gets out of control, it can also be responsible
for anxiety that paralyzes us and prevents us from functioning.
GENERALIZED ANXIETY
DISORDER (GAD)
What
generally distinguishes anxiety from fear is the absence
of any external stimulus that triggers the anxiety reaction.
Actually seeing a snake may trigger fear, while remembering a
snake when you pass by a place where you once saw one may trigger
anxiety. By keeping us away from potential dangers, both fear
and anxiety have significant adaptive value, which is why we
have inherited them from our ancestors. But when anxiety
becomes so recurrent and persistent that it interferes with someone's
normal activities, they may be diagnosed as having generalized
anxiety disorder (GAD).
There are probably a number of factors that
contribute to this disorder. Since it is more common in certain
families, some genetic factors seem to be involved. These factors
might make certain individuals biologically predisposed to GAD,
which they would then develop if certain kinds of triggering external
events occurred in their lives.
In other cases, GAD might be caused by traumatic memories or unresolved
internal conflicts. In many cases, these precipitating factors
and the disorder itself date back to very early childhood.
Most people who have GAD also experience depression and/or panic
attacks. All of these disorders seem to be influenced by certain
neurotransmitters, such as serotonin. GABA and
norepinephrine may also be involved in anxiety disorders.