Michael Lemonick explains How We Get Addicted:
Of course, not everyone becomes an addict. That’s because we have other, more analytical regions that can evaluate consequences and override mere pleasure seeking. Brain imaging is showing exactly how that happens. Paulus, for example, looked at methamphetamine addicts enrolled in a VA hospital’s intensive four-week rehabilitation program. Those who were more likely to relapse in the first year after completing the program were also less able to complete tasks involving cognitive skills and less able to adjust to new rules quickly. This suggested that those patients might also be less adept at using analytical areas of the brain while performing decision-making tasks. Sure enough, brain scans showed that there were reduced levels of activation in the prefrontal cortex, where rational thought can override impulsive behavior. It’s impossible to say if the drugs might have damaged these abilities in the relapsers — an effect rather than a cause of the chemical abuse — but the fact that the cognitive deficit existed in only some of the meth users suggests that there was something innate that was unique to them. To his surprise, Paulus found that 80% to 90% of the time, he could accurately predict who would relapse within a year simply by examining the scans.
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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.