Understanding why drug addicts relapse

by Sarah Nightingale

People who have used cocaine are at high risk for a relapse, even after long drug-free periods.
It’s something families, friends and even addicts are hard pressed to understand.
Researchers in Sweden have made some headway in understanding why it happens and identifying a target for treatment to prevent relapses.
Here’s a synopsis by the American Association for the Advancement of Science website:
Drugs are addictive because they “hijack” the brain‘s reward system, which is actually intended to make it pleasurable to eat and have sex, behaviors that are necessary for survival and reproduction.
This “hijacking” is extremely long-lived and often leads to relapses into abuse, especially when the individual is exposed to stimuli in the surroundings that are associated with the drug.
In an article in the prestigious Journal of Neuroscience the researchers studied mice and showed a brain receptor for the signal substance glutamate (mGluR5) plays a major role in relapses.
“Our findings show that the mice who lacked the receptor were less prone to relapse,” said David Engblom, associate professor of neurobiology at Link?ping University in Sweden.
“This is due the fact that their reaction to reward (cocaine) had not been etched into their memories in the same ways as in normal mice. The receptor seems to be a prerequisite for objects or environments that were previously associated with taking drugs, or something else rewarding, to create a craving.”