Tuesday, July 1, 2014

Is Risky Behavior in Teens "Hard-Wired" into their Brains?

From the New York Times:

Why Teenagers Act Crazy

ADOLESCENCE is practically synonymous in our culture with risk taking,
emotional drama and all forms of outlandish behavior. Until very recently,
the widely accepted explanation for adolescent angst has been
psychological. Developmentally, teenagers face a number of social and
emotional challenges, like starting to separate from their parents, getting
accepted into a peer group and figuring out who they really are. It doesn’t
take a psychoanalyst to realize that these are anxiety-provoking

But there is a darker side to adolescence that, until now, was poorly
understood: a surge during teenage years in anxiety and fearfulness.
Largely because of a quirk of brain development, adolescents, on average,
experience more anxiety and fear and have a harder time learning how not
to be afraid than either children or adults.

Different regions and circuits of the brain mature at very different
rates. It turns out that the brain circuit for processing fear — the amygdala
— is precocious and develops way ahead of the prefrontal cortex, the seat
of reasoning and executive control. This means that adolescents have a
brain that is wired with an enhanced capacity for fear and anxiety, but is
relatively underdeveloped when it comes to calm reasoning.

You may wonder why, if adolescents have such enhanced capacity for
anxiety, they are such novelty seekers and risk takers. It would seem that
the two traits are at odds. The answer, in part, is that the brain’s reward
center, just like its fear circuit, matures earlier than the prefrontal cortex.

That reward center drives much of teenagers’ risky behavior. This
behavioral paradox also helps explain why adolescents are particularly
prone to injury and trauma. The top three killers of teenagers are
accidents, homicide and suicide.

The brain-development lag has huge implications for how we think
about anxiety and how we treat it. It suggests that anxious adolescents
may not be very responsive to psychotherapy that attempts to teach them
to be unafraid, like cognitive behavior therapy, which is zealously
prescribed for teenagers.

What we have learned should also make us think twice — and then
some — about the ever rising use of stimulants in young people, because
these drugs may worsen anxiety and make it harder for teenagers to do
what they are developmentally supposed to do: learn to be unafraid when
it is appropriate to do so.

As a psychiatrist, I’ve treated many adults with various anxiety
disorders, nearly all of whom trace the origin of the problem to their
teenage years. They typically report an uneventful childhood rudely
interrupted by adolescent anxiety. For many, the anxiety was inexplicable
and came out of nowhere.

Of course, most adolescents do not develop anxiety disorders, but
acquire the skill to modulate their fear as their prefrontal cortex matures
in young adulthood, at around age 25. But up to 20 percent of adolescents
in the United States experience a diagnosable anxiety disorder, like
generalized anxiety or panic attacks, probably resulting from a mix of
genetic factors and environmental influences. The prevalence of anxiety
disorders and risky behavior (both of which reflect this developmental
disjunction in the brain) have been relatively steady, which suggests to me
that the biological contribution is very significant.

One of my patients, a 32-year-old man, recalled feeling anxious in
social gatherings as a teenager. “It was viscerally unpleasant and I felt as if
I couldn’t even speak the same language as other people in the room,” he
said. It wasn’t that he disliked human company; rather, socializing in
groups felt dangerous, even though intellectually he knew that wasn’t the
case. He developed a strategy early on to deal with his discomfort: alcohol.
When he drank, he felt relaxed and able to engage. Now treated and sober
for several years, he still has a trace of social anxiety and still wishes for a
drink in anticipation of socializing.

Of course, we all experience anxiety. Among other things, it’s a
normal emotional response to threatening situations. The hallmark of an
anxiety disorder is the persistence of anxiety that causes intense distress
and interferes with functioning even in safe settings, long after any threat
has receded.
We’ve recently learned that adolescents show heightened fear
responses and have difficulty learning how not to be afraid. In one study
using brain M.R.I., researchers at Weill Cornell Medical College and
Stanford University found that when adolescents were shown fearful faces,
they had exaggerated responses in the amygdala compared with children
and adults.

The amygdala is a region buried deep beneath the cortex that is
critical in evaluating and responding to fear. It sends and receives
connections to our prefrontal cortex alerting us to danger even before we
have had time to really think about it. Think of that split-second
adrenaline surge when you see what appears to be a snake out on a hike in
the woods. That instantaneous fear is your amygdala in action. Then you
circle back, take another look and this time your prefrontal cortex tells you
it was just a harmless stick.

Thus, the fear circuit is a two-way street. While we have limited
control over the fear alarm from our amygdala, our prefrontal cortex can
effectively exert top-down control, giving us the ability to more accurately
assess the risk in our environment. Because the prefrontal cortex is one of
the last brain regions to mature, adolescents have far less ability to
modulate emotions.

Fear learning lies at the heart of anxiety and anxiety disorders. This
primitive form of learning allows us to form associations between events
and specific cues and environments that may predict danger. Way back on
the savanna, for example, we would have learned that the rustle in the
grass or the sudden flight of birds might signal a predator — and taken the
cue and run to safety. Without the ability to identify such danger signals,
we would have been lunch long ago.

But once previously threatening cues or situations become safe, we
have to be able to re-evaluate them and suppress our learned fear
associations. People with anxiety disorders have trouble doing this and
experience persistent fear in the absence of threat — better known as

Another patient I saw in consultation recently, a 23-year-old woman,
described how she became anxious when she was younger after seeing a
commercial about asthma. “It made me incredibly worried for no reason,
and I had a panic attack soon after seeing it,” she said. As an older
teenager, she became worried about getting too close to homeless people
and would hold her breath when near them, knowing that “this was crazy
and made no sense.”

B. J. Casey, a professor of psychology and the director of the Sackler
Institute at Weill Cornell Medical College, has studied fear learning in a
group of children, adolescents and adults. Subjects were shown a colored
square at the same time that they were exposed to an aversive noise. The
colored square, previously a neutral stimulus, became associated with an
unpleasant sound and elicited a fear response similar to that elicited by the
sound. What Dr. Casey and her colleagues found was that there were no
differences between the subjects in the acquisition of fear conditioning.

But when Dr. Casey trained the subjects to essentially unlearn the
association between the colored square and the noise — a process called
fear extinction — something very different happened. With fear extinction,
subjects are repeatedly shown the colored square in the absence of the
noise. Now the square, also known as the conditioned stimulus, loses its
ability to elicit a fear response. Dr. Casey discovered that adolescents had a
much harder time “unlearning” the link between the colored square and
the noise than children or adults did.

In effect, adolescents had trouble learning that a cue that was
previously linked to something aversive was now neutral and “safe.” If you
consider that adolescence is a time of exploration when young people
develop greater autonomy, an enhanced capacity for fear and a more
tenacious memory for threatening situations are adaptive and would
confer survival advantage. In fact, the developmental gap between the
amygdala and the prefrontal cortex that is described in humans has been
found across mammalian species, suggesting that this is an evolutionary
advantage. This new understanding about the neurodevelopmental basis
of adolescent anxiety has important implications, too, in how we should
treat anxiety disorders.

One of the most widely used and empirically
supported treatments for anxiety disorders is cognitive behavior therapy, a
form of extinction learning in which a stimulus that is experienced as
frightening is repeatedly presented in a nonthreatening environment. If,
for example, you had a fear of spiders, you would be gradually exposed to
them in a setting where there were no dire consequences and you would
slowly lose your arachnophobia. The paradox is that adolescents are at
increased risk of anxiety disorders in part because of their impaired ability
to successfully extinguish fear associations, yet they may be the least
responsive to desensitization treatments like cognitive behavior therapy
precisely because of this impairment.

This presents a huge clinical challenge since young people are
generally risk takers who are more prone to exposure to trauma as a direct
result of their behavior, to say nothing of those who were exposed to the
horrors of the wars in Iraq and Afghanistan or the mass shootings like
those in Newtown and Aurora. Many of them will go on to develop posttraumatic
stress disorder, which is essentially a form of fear learning. Now
we have good reason to think that exposure therapy alone may not be the
best treatment for them. A recent study of children and adolescents with
anxiety disorders found that only 55 to 60 percent of subjects responded to
either cognitive behavior therapy or an antidepressant alone, but 81
percent responded to a combination of these treatments. And in another
study, there was preliminary evidence that adolescents responded less well
to cognitive behavior therapy than children or adults.

This isn’t to say that cognitive therapy is ineffective for teenagers, but
that because of their relative difficulty in learning to be unafraid, it may
not be the most effective treatment when used on its own.
And there is potentially something else to worry about with our
anxious adolescents: the meteoric rise in their use of psychostimulants like
Ritalin and Adderall. In theory, stimulants could have a negative impact
on the normal developmental trajectory of anxious teenagers.

According to the health care data company IMS Health, prescription
sales for stimulants increased more than fivefold between 2002 and 2012.
This is of potential concern because it is well known from both human and
animal studies that stimulants enhance learning and, in particular, fear
conditioning. Stimulants, just like emotionally charged experiences, cause
the release of norepinephrine — a close relative of adrenaline — in the
brain and facilitate memory formation. That’s the reason we can easily
forget where we put our keys but will never forget the details of being

Might our promiscuous use of stimulants impair the ability of
adolescents to suppress learned fear — something that is a normal part of
development — and make them more fearful adults? And could stimulants
unwittingly increase the risk of PTSD in adolescents exposed to trauma? In
truth, we haven’t a clue.

But we do know this: Adolescents are not just carefree novelty seekers
and risk takers; they are uniquely vulnerable to anxiety and have a hard
time learning to be unafraid of passing dangers. Parents have to realize
that adolescent anxiety is to be expected, and to comfort their teenagers —
and themselves — by reminding them that they will grow up and out of it
soon enough.

Richard A. Friedman is a professor of clinical psychiatry and the director of the psychopharmacology
clinic at the Weill Cornell Medical College.
7/1/2014 Why Teenagers Act Crazy - NYTimes.com
http://www.nytimes.com/2014/06/29/opinion/sunday/why-teenagers-act-crazy.html?emc=eta1&_r=0 7/7
A version of this op-ed appears in print on June 29, 2014, on page SR1 of the New York edition
with the headline: Why Teenagers Act Crazy.
© 2014 The New York Times Company

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