Neurology May Better Addiction Therapy

Nora Volkow, the director of the National Institute on Drug Abuse, last night outlined a series of scientific findings which may revolutionize treatment for drug addiction.

In a lecture entitled “Drug Addiction: the Neurobiology of Disrupted Free Will” at Harvard Medical School, she emphasized the genetic component of a person’s sensitivity to drugs, as well as the link between drug use and memory.

Volkow’s team at the Brookhaven National Laboratory has made scientific breakthroughs indicating that traditional treatment for drug addiction may not be the only way—or even the best way—to reduce drug abusers’ cravings.

Her findings reveal the role in addiction played by the section of the brain responsible for self control, as well as the part associated with pleasure.

Volkow said her team had proved this with a number of experiments, including one in which rats were administered cocaine upon an auditory cue.

When the experiment was repeated with the cues but without the drugs, the rats’ levels of dopamine were nearly the same, suggesting that the drug alone is not responsible for the pleasure experienced by drug addicts.

A similar result was observed in an experiment with humans which did not involve any drugs at all.

Subjects were shown both neutral control videos and videos that showed people using cocaine. Scientists observed that subjects’ dopamine levels increased drastically when shown videos of drug use.

The experiments, Volkow said, demonstrate the strong connection between memory and craving, and suggest that more effective treatments might focus on disrupting memory rather than affecting only the rewards a drug user experiences.

Addictive behavior is often driven by the memory of past drug use rather than the expected rewards of future consumption, said A. Eden Evins, an associate professor of psychiatry at Harvard Medical School, after the lecture.

More experiments show that addicts have a decreased sensitivity to the effects of drugs, can only be partly explained by tolerance, Volkow said.

Neurotransmitters, the passages which carry electrical signals between neurons, can be deadened after years of drug use, Volkow said, asserting that gene therapy might be able to replace addicts’ lost receptors and help reduce their cravings.

This careful study of neurotransmitters and of gene treatments developed for the rats could lead to more effective drug rehabilitation medicine in the very near future, she said.

“The old methods have been...to give treatment that reduces the reward from drugs,” said Evins.

Nicolas R. Bolo, an investigator at the neuroimaging center at Harvard’s McLean Hospital, said he agreed that research at the Brookhaven National Laboratory could lead to new drug treatments.

“I think we will [see them] because of that better understanding,” he said.