Amnesia Explained
Why are drug-taking triggers strong enough to obliterate the best rational intentions? Why does amnesia strike so swiftly and thoroughly, returning one to addict insanity as if by instinct? Why do relapsers sometimes say they were “struck drunk”? Neuroscientists say it results from long-term changes to the dopamine system by drug abuse, and the lasting impact it has on memory, leaving the brain vulnerable to the seduction of intoxication long after detox.1
Neuroscientists say it results from long-term changes to the dopamine system frpm drug abuse and the lasting impact it has on memory, leaving the brain vulnerable to the seduction of intoxication long after detox.1
What rehab called “relapse triggers,” scientists refer to as “cues,” powerful emotional memories evoking drug taking. A cue might be the sight of a syringe, a beer commercial, or a drinking song on the radio. Dr. Anna Rose Childress, a psychiatrist at the University of Pennsylvania, has conducted experiments that show that drug-taking cues prompt the brain to release a spurt of dopamine. “This increase in dopamine feels similar to a small dose of the drug itself,” she says. Some people report they can taste drugs in the back of their throats, though they haven’t had any.3 “They’re having a miniature high before they even get there,” Dr. Childress says. “…[I]t’s a primer, it’s a seductive pull.”4
This seductive pull happens so swiftly as to be almost automatic. In a later study by Dr. Childress and others, sober cocaine addicts underwent fMRIs while looking at a series of photos including drug cues like pictures of cocaine. Though the pictures were flashed for a mere 33 milliseconds, the subjects’ Limbic “reward” Systems were still stimulated by them. (Interestingly, the brain regions activated by drug cues overlapped substantially with those stimulated by sexual images. This suggests that addictive drugs can usurp brain regions that normally recognize other rewards, explaining why addicts forego other basic needs in favor of drugs.)5
The seductive pull of drug cues also operate unconsciously. Dr. Nora Volkow of the Brookhaven National Lab, performed brain scans of cocaine addicts watching two videos: one of nature scenes, the other of people using cocaine. She found that drug-taking scenes spiked dopamine in proportion to the addicts’ subjective reporting of craving. This illustrates the enormous power of those cuesand that they work beyond cognizance. Dr. Volkow says, “For these people, their lives and experiences have taught them that when they see others using cocaine, they’re probably about to get rewarded with drugs too. So even though they consciously knew they weren’t going to get cocaine after watching the video, their brains had learned to expect the reward.”6
Amnesia happens because the spike in dopamine the addict brain experiences on seeing a cue overpowers the planning and decision-making frontal cortex.7 The addict’s thought process over-stresses the emotional short-term need for drugs over the rational long-term benefits of sobriety and the negative consequences of drug use. That short-term need pushes the rational aside so quickly and unconsciously, it feels instinctive. That’s alcoholics who relapse feel like they were “struck drunk.”
1. Alcohol’s Toll on Fetuses: Even Worse than Thought; New York Times, Nov. 4, 2003.
2. How Chemistry Has Enhanced Scientists’ Ability to See Inside Brain, medicalnewstoday.com,September 17, 2006; Smoking Tied to Kidney and Spleen Damage, New York Times, September 9, 2003.
3. Genetic Studies Promise a Path to Better Treatment of Addictions; New York Times, Nov. 14, 2000.
4. Brain Study Illustrates Intense Pull of Cocaine; AP/San Francisco Chronicle, April 11, 2003.
5. Brain Study Illustrates Intense Pull of Cocaine; AP/San Francisco Chronicle, April 11, 2003.
6. An Anti-Addiction Pill?; New York Times Magazine, June 25, 2006.
7. An Anti-Addiction Pill?; New York Times Magazine, June 25, 2006.
