Uri Shalev explores the mystery of drug relapse

By Frank Kuin

Uri Shalev is trying to find out why drug addicts tend to undo their own efforts to kick the habit.

Shalev, who has joined Concordia as Canada Research Chair in the Neurobiology of Drug Abuse, Tier 2, studies the phenomenon of relapse to drug seeking.

Working in the university’s Centre for Studies in Behavioural Neurobiology in the Department of Psychology, he examines rats that have been taken off hard drugs after having been made addicted to them. He is learning more about what triggers them to go back.

His research may help to find more effective treatments for human drug addicts.

“Relapse is one of the most significant problems in the treatment of drug abuse,” he said, noting that a “huge” percentage of addicts who kick the habit, between 70 and 80 per cent, eventually take it back up.

“Every smoker knows that you can quit for a while if you want, but most adults will relapse.

“My research is on the reasons for that relapse: Why do people who sometimes can be abstinent for years, start to take drugs again, even though they know that they have really negative consequences?

“Something is very powerful about this behaviour that makes them go back.”

At the moment, Shalev is exploring a possible connection between relapse to drug seeking and food deprivation. “One of the things that I found is that food deprivation is a strong cue for drug seeking,” he said.

To find out more about the brain mechanisms involved in this link, Shalev does lab work with rats that have learned to self-administer a hard drug, like heroin, by pressing a lever several times an hour.

When the drug is taken away, the animals learn that there is no use pressing the lever any more. But when they are deprived of food, they will have a greater tendency to start pressing it again.

Shalev’s research is focused on the neurochemicals in the brain at that stage. Once the experiment is finished, he will remove the brain to “take a snapshot” of it in order to examine which areas of the brain and which so-called “neurotransmitters” are involved.

“This gives you a clue of activity going on in the brain,” he said.

Alternatively, he will manipulate the animals’ brain systems by administering drugs that shut off specific brain functions, by blocking the system that is involved in reward, for instance.

“Food and drugs probably have shared neuromechanisms,” he said. People who suffer from eating disorders such as bulimia tend to go on similar binges as drug addicts.

To know more about such connections would have important practical implications, Shalev observed.

“Once you know what systems are involved, the probability that you’ll find a cure is higher. When you’re just shooting in the dark looking for a treatment, you might get lucky. But it’s easier when you have a target.”

In his methodology, Shalev is building on his previous research. His original interest has been in mental disorders, especially schizophrenia. He noted that addiction is a disorder, and similar brain systems are involved.

Indeed, “it’s very common for schizophrenics to have a drug problem.” He hopes to pursue further research in that area in the future.

For now, addiction and relapse are his main concerns. As a researcher working with drugs such as heroin, he has become accustomed to a tightly controlled environment, he said.

His research is subject to very strict regulations, including special permits, small quantities of the substance imported from licensed manufacturers, a secure safe with an alarm system, and requirements for precise log-keeping.

He can even joke a little about the fact that he’s working with a substance that is highly lucrative outside the research environment. “I cannot start an operation on the side,” he said, smiling.