(3 of 4)
"The changes induced by addiction do not just involve one system," says Volkow. "There are some areas in which the changes persist even after two years." One area of delayed rebound involves learning. Somehow in methamphetamine abusers, the ability to learn some new things remained affected after 14 months of abstinence. "Does treatment push the brain back to normal," asks NIDA's Frascella, "or does it push it back in different ways?"
If the kind of damage that lingers in an addict's learning abilities also hangs on in behavioral areas, this could explain why rehabilitation programs that rely on cognitive therapy--teaching new ways to think about the need for a substance and the consequences of using it--may not always be effective, especially in the first weeks and months after getting clean. "Therapy is a learning process," notes Vocci. "We are trying to get [addicts] to change cognition and behavior at a time when they are least able to do so."
One important discovery: evidence is building to support the 90-day rehabilitation model, which was stumbled upon by AA (new members are advised to attend a meeting a day for the first 90 days) and is the duration of a typical stint in a drug-treatment program. It turns out that this is just about how long it takes for the brain to reset itself and shake off the immediate influence of a drug. Researchers at Yale University have documented what they call the sleeper effect--a gradual re-engaging of proper decision making and analytical functions in the brain's prefrontal cortex--after an addict has abstained for at least 90 days.
This work has led to research on cognitive enhancers, or compounds that may amplify connections in the prefrontal cortex to speed up the natural reversal. Such enhancement would give the higher regions of the brain a fighting chance against the amygdala, a more basal region that plays a role in priming the dopamine-reward system when certain cues suggest imminent pleasure--anything from the sight of white powder that looks like cocaine to spending time with friends you used to drink with. It's that conditioned reflex--identical to the one that caused Ivan Pavlov's famed dog to salivate at the ringing of a bell after it learned to associate the sound with food--that unleashes a craving. And it's that phenomenon that was the purpose of my brain scans at McLean, one of the world's premier centers for addiction research.
In my heyday, I would often drink even when I knew it was a terrible idea--and the urge was hardest to resist when I was with my drinking buddies, hearing the clink of glasses and bottles, seeing others imbibe and smelling the aroma of wine or beer. The researchers at McLean have invented a machine that wafts such odors directly into the nostrils of a subject undergoing an fMRI scan in order to see how the brain reacts. The reward circuitry in the brain of a newly recovering alcoholic should light up like a Christmas tree when stimulated by one of these alluring smells.
I chose dark beer, my absolute favorite, from their impressive stock. But I haven't gotten high for more than a quarter-century; it was an open question whether I would react that way. So after an interview with a staff psychiatrist to make sure I would be able to handle it if I experienced a craving, I was fitted with a tube that carried beer aroma from a vaporizer into my nose. I was then slid into the machine to inhale that still familiar odor while the fMRI did its work.
Even if the smells triggered a strong desire to drink, I had long since learned ways to talk myself out of it--or find someone to help me do so. Like the 90-day drying-out period that turns out to parallel the brain's recovery cycle, such a strategy is in line with other new theories of addiction. Scientists say extinguishing urges is not a matter of getting the feelings to fade but of helping the addict learn a new form of conditioning, one that allows the brain's cognitive power to shout down the amygdala and other lower regions. "What has to happen for that cue to extinguish is not for the amygdala to become weaker but for the frontal cortex to become stronger," says Vocci.
While such relearning has not been studied formally in humans, Vocci believes it will work, on the basis of studies involving, of all things, phobias. It turns out that phobias and drugs exploit the same struggle between high and low circuits in the brain. People placed in a virtual-reality glass elevator and treated with the antibiotic D-cycloserine were better able to overcome their fear of heights than those without benefit of the drug. Says Vocci: "I never thought we would have drugs that affect cognition in such a specific way."
Such surprises have even allowed experts to speculate whether addiction can ever be cured. That notion goes firmly against current beliefs. A rehabilitated addict is always in recovery because cured suggests that resuming drinking or smoking or shooting up is a safe possibility--whose downside could be devastating. But there are hints that a cure might not in principle be impossible. A recent study showed that tobacco smokers who suffered a stroke that damaged the insula (a region of the brain involved in emotional, gut-instinct perceptions) no longer felt a desire for nicotine.
That's exciting, but because the insula is so critical to other brain functions--perceiving danger, anticipating threats--damaging this area isn't something you would ever want to do intentionally. With so many of the brain's systems entangled with one another, it could prove impossible to adjust just one without throwing the others into imbalance.
Nevertheless, says Volkow, "addiction is a medical condition. We have to recognize that medications can reverse the pathology of the disease. We have to force ourselves to think about a cure because if we don't, it will never happen." Still, she is quick to admit that just contemplating new ideas doesn't make them so. The brain functions that addiction commandeers may simply be so complex that sufferers, as 12-step recovery programs have emphasized for decades, never lose their vulnerability to their drug of choice, no matter how healthy their brains might eventually look.
I'm probably a case in point. My brain barely lit up in response to the smell of beer inside the fMRI at McLean. "This is actually valuable information for you as an individual," said Scott Lukas, director of the hospital's behavioral psychopharmacology research laboratory and a professor at Harvard Medical School who ran the tests. "It means that your brain's sensitivity to beer cues has long passed."