Drug addiction is a disease of the brain, according to Dr. Nora
Volkow, director of the National Institute of Drug Abuse. Volkow
delivered the fifth annual Spirit Lecture on Mar. 20 at NIEHS.
The annual event honors "women sustaining the American spirit." Volkow's
presentation aimed at changing the way people think about drug
abuse, to ensure they understand that they are dealing with a medical
disease, not a lack of will.
|NIDA director Dr. Nora Volkow talks with
NIEHS director Dr. David Schwartz before she delivered the
fifth annual Spirit Lecture.
Chronic exposure to drugs creates changes in the brain that cause
addiction, which, by definition, a person has no control over,
she said. While vulnerability to drug addiction is partially genetically
determined, exposure at certain stages — such as adolescence — is much
more harmful than exposure at other stages. Drug abuse, Volkow
said, is a developmental disease that often begins in adolescence,
and sometimes in late childhood. In adolescents' developing brains,
the target areas for drugs of abuse are significantly larger than
in adults, while the areas that inhibit emotion or suppress impulses
are not fully developed in youngsters, she said.
It is important to recognize that the earlier someone begins taking
drugs, the more severe the resulting addiction will likely be,
she explained. Volkow also said environmental factors such as the
availability of drugs, family support, poverty and crime all play
a role in either protecting people from or putting them at risk
for drug abuse.
She said animal studies have shown that if you stress an animal,
it is more likely to take drugs. Therefore, Volkow noted, applying
stressors is akin to stimulating drug abuse. A primate study conducted
by Wake Forest University researchers showed that dominant animals
within the social structure had more dopamine receptors, are less
likely to experience stress and are less susceptible to drug addiction.
By contrast, subordinate animals had fewer receptors and were more
vulnerable to addiction. While human social structures are more
complex — individuals can be dominant in some areas of their life
while being subordinate in others — the social environment and related
stress clearly emerge as important factors in addiction, Volkow
She said addressing the problem of addiction requires an approach
that considers social factors, behavioral factors, neuronal circuits,
protein expression and the genome. Only then can targeted interventions
be created to protect people at greater risk for drug addiction,
A physician and psychiatrist, Volkow was appointed director of
NIDA in 2003. She pioneered the use of brain imaging to investigate
toxic effects of drugs.
Before joining NIDA, Volkow was a professor in the department
of psychiatry and was associate dean of the medical school at the
State University of New York, Stony Brook. She is a member of the
National Academy of Sciences' Institute of Medicine.