Pubdate: Tue, 04 Apr 2006
Source: New York Times ( NY )
Copyright: 2006 The New York Times Company
Author: Benedict Carey
Bookmark: (Cocaine)
Bookmark: (Heroin)


Play hooky, disappear for the weekend, have a fling, binge-shop like 
a Wall Street divorcee.  Spontaneity can be a healthy defiance of 
routine, an expression of starved desire, some psychologists say.

Yet for scientists who study  mental illness and addiction, impulsive 
behavior -- the tendency to act or react with little thought -- has 
emerged as an all-purpose plague.

In recent years, studies have linked impulsiveness to higher risks 
of  smoking, drinking and drug abuse.  People who attempt  suicide 
score highly on measures of impulsivity, as do adolescents with 
eating problems.  Aggression, compulsive gambling, severe personality 
disorders and attention deficit problems are all associated with high 
impulsiveness, a problem that affects an estimated 9 percent of 
Americans, according to a nationwide mental health survey completed last year.

Now researchers have begun to resolve the contrary nature of 
impulsivity, identifying the elements that distinguish benign 
experimentation from self-destructive acts.  The latest work, in 
brain research and psychological studies, helps explain how impulsive 
tendencies develop and when they can lead people astray.  A potent 
combination of genes and emotionally disorienting early experiences 
puts people at high risk, as do some very familiar personal instincts.

"What we're seeing now," said Charles S.  Carver, a psychologist at 
the University of Miami in Coral Gables, Fla., "is a rapid 
convergence of evidence indicating that when the prefrontal cortical 
areas of the brain, the brain's supervisory management system, are 
not functioning well, this interferes with deliberative behavior, and 
the consequences are often unpleasant."

Few experts dispute that impulsiveness pays off in some situations 
and, perhaps, had evolutionary benefits.  When life is short and 
dangerous, and resources are scarce, there is a premium on quick 
response.  In studies of baboons and monkeys, researchers have found 
that animals that are impulsive as adolescents often become dominant 
as adults, when they moderate their confrontational urges.

In humans, impulsive behavior typically peaks in adolescence, when 
the prefrontal areas of the brain continue to develop, or soon after, 
in the young adult years, when it is culturally expected that people 
will test their limits, psychologists have found.

Yet new research suggests that a taste for danger or conflict is not 
enough to produce persistent, ruinous impulsivity.

In a study published online last month in The Journal of Psychiatric 
Research, Janine D.  Flory, a psychologist at the Mount Sinai School 
of Medicine in Manhattan, led a team of investigators who studied 351 
healthy adults and 70 others with impulse-related disorders like 
antisocial and borderline personality disorders.  The participants 
took a battery of tests to measure inhibition, appetite for risk and 
the inclination to plan.

Analyzing the responses to questions intended to gauge thrill seeking 
like, "I like to explore a strange city or section of town by myself, 
even if it means getting lost," and, "I like to try foods I've never 
tried before," the researchers found that an appetite for risk was 
associated with smoking in both groups.

But in the healthy volunteers, the appetite was also associated with 
higher education.  In previous studies, healthy risk seekers scored 
highly for curiosity and openness to new experiences.  On 
measurements of instinctive planning - "I am better at saving money 
than most people" and "I hate to make decisions based on first 
impressions"- the researchers found that less deliberative habits 
were related to heavy drinking in the healthy group and the troubled group.

In cases with personality disorders, deficits in planning were also 
associated with a history of suicide attempts.  The combination of 
sensation seeking and lack of deliberation characterizes millions of 
healthy people but appears to be extreme in those whose impulsivity 
leads to chronic trouble or mental illness, Dr.  Flory said.

"The way I think of it is that one factor has to do with the urges 
people have, and the other has to do with the brakes they apply," she said.

How and when people apply the brakes is crucial to distinguishing 
those who can flirt with regular heroin or cocaine use while 
finishing an Ivy League degree and those who die trying.

The people who can binge, gamble or try hard drugs and get away with 
it have a native cunning when it comes to risk, this and other 
studies suggest.  They are prepared for the dangers like a mountain 
climber or they sample risk, in effect, by semiconsciously hedging 
their behavior - sipping their cocktails slowly, inhaling partly or 
keeping one toe on the cliff's edge, poised for retreat.

"These are highly self-directed people," said C.  Robert Cloninger, a 
professor of psychiatry and genetics at Washington University in 
St.  Louis and author of "Feeling Good: The Science of Well-Being." 
"They have goals and are resourceful in pursuing them."

Those who are upended by their own impulses, by contrast, are more 
likely to trust their first impressions implicitly and absolutely, 
the studies suggest.

"I am a very intuitive person, I can tell very quickly when someone's 
lying to me, when they're telling a shaggy-dog story," said Thomas 
Crepeau, 55, a computer systems analyst in Washington who said his 
impulsive temper helped worsen a contentious marriage.

Mr.  Crepeau, who has since benefited from therapy, said he used to 
act on his hunches immediately.  "Other people might allow me 20 
words before cutting in, but I would allow them four," he said.  "I 
never had the patience to just wait it out and see if the other 
person was wrong."

This difference in ability to hedge or self-regulate is partly based 
in genetic variation, experts say.  In a study published in March, 
investigators at the National Institute of Mental Health took blood 
samples from 142 healthy volunteers and analyzed a gene called 
MAOA.  The gene directs the body to produce an enzyme that reduces 
the activity of a brain chemical called serotonin, which strongly 
influences mood.  Earlier studies have linked variations in this gene 
to impulsive aggression.

The researchers conducted M.R.I.  scans on participants' brains while 
they were performing tasks intended to measure impulse control.  In 
one of the tests, the participants watched as a computer screen 
presented a series of arrows, boxes and X's, three at a time, as a 
slot machine does.

The patterns appeared in quick succession, and the participants were 
instructed to hit a button indicating which way the arrow was 
pointing.  They also had to restrain from hitting the button when one 
particular pattern appeared.  Their mistakes provided a measure of 
how well they could restrain their reflexes.

The researchers found that, during the computer game, men who had one 
common MAOA variant, known as the "high-risk" variant, showed 
significantly less activation than peers with the "low risk" version 
of the gene in an area called the dorsal anterior cingulate.  The 
cingulate is part of the brain's prefrontal area - its supervisory 
manager - which is involved in shaping deliberate behavior, in 
measuring a proper response or reflex.

The participants in the study with the high-risk gene also had 
deficits in areas of the brain involved in moderating emotion, 
supporting many earlier studies finding similar gene-related differences.

"On the one hand, these deficits in emotional regulation set people 
up for strong emotional reactions early in life and make them more 
vulnerable to trauma, we believe," said Dr.  Andreas 
Meyer-Lindenberg, the study's lead author.  "On the other hand, the 
deficit in cognitive, inhibitory function creates a propensity to act 
on those emotions later in life."

And life never stops testing those supervisory mental skills.  Drug 
use weakens deliberative regulating skills quickly and cumulatively 
over time.  Coping with periods of extreme stress at any age - 
starting a new job, breaking up with a romantic partner, recovering 
from a car accident - can overload the prefrontal regions, leaving 
fewer resources available to manage emotions, Dr.  Carver said.

One reason true impulsivity has been difficult to capture in the lab, 
said Dr.  Martha Farrah, director of the Center for Cognitive 
Neuroscience at the University of Pennsylvania, is precisely because 
"it is most manifest in these very high-stakes situations, when 
people are trying to get what they want, to stay focused, maybe 
trying to kick a drug habit." And that is when they break down.

None of which is to deny the power of early psychological wounds, 
regardless of genetic makeup.

People with borderline personality disorder, for example, an 
enigmatic condition characterized by neediness, emotional reactions 
and self-destructive behavior like self-mutilation, often misread 
others' motives and are savagely impulsive in response.  "The 
impulsive behavior always has specific meanings for them," said 
Dr.  Glen Gabbard, a psychiatrist at the Baylor College of Medicine in Houston.

One of his patients, he said, recently called her boyfriend at work, 
who told her he couldn't talk just then, he was swamped.  She took 
that to mean that he was about to dump her.

"She called him back immediately after hanging up and broke up with 
him on the spot, as a pre-emptive strike," Dr.  Gabbard said.

For her and many others, he said: "It is the psychological meaning of 
the event that matters most, and for her it was abandonment.  Her own 
father left the family when she was 4 years old, and she sees 
abandonment everywhere."

In Mr.  Crepeau's case, he enrolled in a "compassion power" 
group-therapy workshop and learned that his contentious nature grew 
in part out of a history of being dismissed and ignored.  Once he 
understood how this history shaped his impulsiveness, he was able to 
begin delaying his reactions.

Mr.  Crepeau now teaches workshops that help people deal with 
impulsivity and other relationship problems.  In a recent class, he 
had to contain himself when one of the workshop attendees, asked to 
present a homework assignment, took the opportunity to brag at length 
about his accomplishments.

"I couldn't believe this guy; not long ago I would have stepped in" 
and told him off, Mr.  Crepeau said.  "But I just waited, and 
politely told him he needed to do the assignment over."
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