Recovering from a drug addiction is no easy task, especially when said drug has changed your brain to the point that relapse is almost expected. A recent study conducted at the University of East Anglia has found that using cocaine results in “profound changes” in the brain that makes relapsing due to stress much more common among addicts. Fortunately, this research has also given way to potential mechanisms that can prevent relapse under stressful conditions.

“Relapse among cocaine addicts is a major problem,” Dr. Peter McCormick, from UEA's School of Pharmacy, said in a statement. “We wanted to find out what causes it. We had speculated that there might be a direct communication between neuroreceptors controlling stress and reward. When we tested this, we found this to indeed be the case.”

McCormick and his colleagues compared the effects of cocaine on the brain cells of rats and live rats, focusing specifically on each rat’s “cocaine seeking” response to stress. To assess the effects of cocaine use, the research team identified two neuropeptides in the area of the brain responsible for reward, motivation, and drug addiction. Neuropeptides refer to messenger molecules that operate the brain’s communication systems by relaying information between neurons.

The release of these two specific neuropeptides influences activity in this area of the brain, while exposure to cocaine causes these “profound changes” at the brain’s neuroreceptor level. Disrupted interaction between receptors increase the addict’s risk for relapse when introduced to stressful situations. It’s not all bad news, though. Further research revealed that the risk for a stress-induced relapse can be lowered by repairing these broken interactions.

“Although our study is in rodents, the same receptors have been shown to impact human stress and drug addiction,” McCormick explained. “Cocaine has a relatively unique effect on the brain. However, the reward center is crucial for addictive behaviors. We identify a potential mechanism for protection against such relapse. This research lays the groundwork for the development of such approaches.”

According to the National Institute on Drug Abuse, cocaine increases levels of the neurotransmitter dopamine in the brain, which regulates pleasure and movement. This flood of dopamine results in the “high” cocaine addicts experience. As someone continues to use cocaine, their brain systems, most notably the brain’s reward system, experience changes that lead to addiction. Repeated use also results in tolerance that causes the addict to require more cocaine to reach their “high.”

"Studies on post-traumatic stress disorder have shown traumatic events can have profound influences on receptors in this region of the brain, perhaps rendering soldiers more prone to addiction,” McCormick added. “Although speculative, it would not surprise me to see similar results in other situations, whether drug or stress related.”

Source: McCormick P, et al. The Journal of Neuroscience. 2015.