Timothy Condon, Ph.D.: "We must treat addiction as a chronic,
relapsing medical disorder." National Institute on Drug Abuse
National Institute on Drug Abuse (NIDA) Director Nora Volkow, M.D., added
another award to her ever-growing collection last month with the presentation
of the Founders' Award from the American Academy of Addiction Psychiatry
(AAAP). In bestowing the award, AAAP President Kathleen Brady, M.D., Ph.D.,
said Volkow "exemplifies the reality of addiction as a chronic,
relapsing medical disorder that should be treated by physicians."
Due to scheduling conflicts, Volkow was unable to accept the award in
person; however, she sent Timothy Condon, Ph.D., her deputy director at NIDA,
to the group's annual meeting in Scottsdale, Ariz.
The work of Volkow and many of those in attendance, Condon told the group,
has led to "phenomenal advances in science which have helped all of us
to learn that addiction is truly a disease—not a behavioral problem, not
a lack of moral fiber."
But fundamental questions continue to elude complete answers.
"What do we know today about vulnerability?" Condon asked."
Why do some become addicted, while others do not?" Clearly, he
said, it takes both a genetic predisposition to addiction as well as an
environment in which substances of abuse are either available or promoted.
"Genes do not act on their own; however, it is a complex interaction
between genes and environment, most notably during adolescence, that leads to
The discovery over the last several years that neuronal circuits continue
to develop throughout adolescence and into adulthood provoked a "marked
change in thinking" in the neurosciences, Condon said. And that
discovery is very important to the science of addiction and potentially its
"How do drugs of abuse impact a plastic, evolving adolescent
brain?" Condon asked. While a large amount of data exists in adult
populations linking exposure to drugs of abuse to changes in dopamine
receptors in specific brain regions, "we have very few human data in
adolescents." Some adolescent animal data are available, said Condon,
and those data suggest changes in dopamine receptors in response to adolescent
exposure to such substances as nicotine and cannabinoids. But, he added, much
is still to be learned.
Addiction researchers have known for some time that substance abuse is tied
in some way to changes in the brain's circuits that utilize dopamine, Condon
"Dopamine is the neurotransmitter involved in all reward/reinforcing
circuits in the brain, not only for drugs," he added, "but also
for things like sex and food." Yet new research is now showing that
dopamine is not alone.
"We also know that glutamate, GABA, and possibly cannabinoid
receptors may be involved [in modulating substance abuse behaviors]. And we've
learned a lot about the circuits in the limbic system and how prolonged
exposure to drugs of abuse changes these circuits," Condon added."
We've been able to see dramatic reductions in striatal dopamine
receptors in individuals addicted to heroin, cocaine, ethanol, and
Addiction researchers have also discovered a great deal about craving,
Condon continued, and how someone who is addicted to a substance of abuse
shows abnormally elevated activation of brain circuits in the cingulate cortex
and inferior cingulate gyrus.
Yet how these structural and functional changes in the brain caused by drug
abuse lead to addiction is not clear-cut; however, addiction neuroscientists
have learned two points: First, "comorbidity is absolutely the rule, not
the exception," Condon said, "and we have to get others to
understand this," not only from a clinical viewpoint but also from an
administrative viewpoint, including reimbursement issues.
Second, "Is there recovery?" Condon asked. "Of course
there is. But do these physical changes in the brain go back to baseline [when
an addicted individual is no longer exposed to the substance of abuse]?"
Some data, including Volkow's own work at the Brookhaven National Laboratories
prior to joining NIDA, indicate the brain does repair some of the damage.
"Above all, we know that comorbidity is the rule, not the
exception," Condon said. "And we must treat addiction as a
chronic, relapsing disorder." The addiction psychiatry field must become
better at spreading that message, he added.
"So where are we going with all this?" asked Condon."
Research training and mentor grants continue to be ramped up, and the
institute is "going to put [its] money where [its] mouth is in training
the next generation of addiction psychiatrists."
Future NIDA initiatives include focusing on prescription drug
abuse—particularly opiates, Condon said, as well as looking at the"
social neuroscience" issues of clique or group interactions that
support or reinforce addictive behaviors. Genetic influences in substance
abuse weigh heavily.
Finally, Condon concluded, "we are advancing the science [of
addiction], but we must still erase the stigma."
More information on the National Institute on Drug Abuse and its
research and clinical programs is posted at<www.drugabuse.gov>.▪