HOW THE BRAIN GETS ADDICTED TO GAMBLING
In
the past, the psychiatric community generally regarded pathological gambling as
more of a compulsion than an addiction—a behavior primarily motivated by the
need to relieve anxiety rather than a craving for intense pleasure. In the
1980s, while updating the Diagnostic and Statistical Manual of Mental Disorders
(DSM), the American Psychiatric Association (APA) officially classified
pathological gambling as an impulse-control disorder—a fuzzy label for a group
of somewhat related illnesses that, at the time, included kleptomania,
pyromania and trichotillomania (hairpulling). In what has come to be regarded
as a landmark decision, the association moved pathological gambling to the
addictions chapter in the manual's latest edition, the DSM-5, published this
past May. The decision, which followed 15 years of deliberation, reflects a new
understanding of the biology underlying addiction and has already changed the
way psychiatrists help people who cannot stop gambling.
The
APA based its decision on numerous recent studies in psychology, neuroscience
and genetics demonstrating that gambling and drug addiction are far more
similar than previously realized. Research in the past two decades has
dramatically improved neuroscientists' working model of how the brain changes
as an addiction develops. In the middle of our cranium, a series of circuits
known as the reward system links various scattered brain regions involved in
memory, movement, pleasure and motivation. When we engage in an activity that
keeps us alive or helps us pass on our genes, neurons in the reward system
squirt out a chemical messenger called dopamine, giving us a little wave of
satisfaction and encouraging us to make a habit of enjoying hearty meals and
romps in the sack. When stimulated by amphetamine, cocaine or other addictive
drugs, the reward system disperses up to 10 times more dopamine than usual.
Continuous
use of such drugs robs them of their power to induce euphoria. Addictive
substances keep the brain so awash in dopamine that it eventually adapts by
producing less of the molecule and becoming less responsive to its effects. As
a consequence, addicts build up a tolerance to a drug, needing larger and
larger amounts to get high. In severe addiction, people also go through
withdrawal—they feel physically ill, cannot sleep and shake uncontrollably—if
their brain is deprived of a dopamine-stimulating substance for too long. At
the same time, neural pathways connecting the reward circuit to the prefrontal
cortex weaken. Resting just above and behind the eyes, the prefrontal cortex
helps people tame impulses. In other words, the more an addict uses a drug, the
harder it becomes to stop.
Research
to date shows that pathological gamblers and drug addicts share many of the
same genetic predispositions for impulsivity and reward seeking. Just as
substance addicts require increasingly strong hits to get high, compulsive
gamblers pursue ever riskier ventures. Likewise, both drug addicts and problem
gamblers endure symptoms of withdrawal when separated from the chemical or
thrill they desire. And a few studies suggest that some people are especially
vulnerable to both drug addiction and compulsive gambling because their reward
circuitry is inherently underactive—which may partially explain why they seek
big thrills in the first place.
Even
more compelling, neuroscientists have learned that drugs and gambling alter
many of the same brain circuits in similar ways. These insights come from
studies of blood flow and electrical activity in people's brains as they
complete various tasks on computers that either mimic casino games or test
their impulse control. In some experiments, virtual cards selected from
different decks earn or lose a player money; other tasks challenge someone to
respond quickly to certain images that flash on a screen but not to react to
others.
A
new understanding of compulsive gambling has also helped scientists redefine
addiction itself. Whereas experts used to think of addiction as dependency on a
chemical, they now define it as repeatedly pursuing a rewarding experience
despite serious repercussions. That experience could be the high of cocaine or
heroin or the thrill of doubling one's money at the casino. “The past idea was
that you need to ingest a drug that changes neurochemistry in the brain to get
addicted, but we now know that just about anything we do alters the brain,”
says Timothy Fong, a psychiatrist and addiction expert at the University of
California, Los Angeles. “It makes sense that some highly rewarding behaviors,
like gambling, can cause dramatic [physical] changes, too.”
SOURCE:https://www.youtube.com/watch?v=BF5SzIN63w8
SOURCE:https://www.scientificamerican.com/article/how-the-brain-gets-addicted-to-gambling/
