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Drug paraphernalia activates different brain areas in dependent, non-dependent users

Dependent and non-dependent marijuana users’ brains react differently to drug paraphernalia triggers, according to recent study findings published in Drug and Alcohol Dependence.

“We know that people have a hard time staying abstinent because seeing cues for the drug use triggers this intense desire to seek out the drugs,” Francesca M. Filbey, PhD, professor at the Center for BrainHealth at the University of Texas at Dallas, said in a press release. “That’s a clinically validated phenomenon and behavioral studies have also shown this to be the case. What we didn’t know was what was driving those effects in the brain.”

Francesca M. Filbey

Filbey and colleagues evaluated 71 cannabis users, 31 of whom were classified as dependent whereas the rest were non-dependent users (n=24), to determine functional connectivity during exposure to drug-related cues. Functional MRI (fMRI) was used to measure brain activity. During fMRI, participants were given either a marijuana pipe or pencil of the same size they could see and feel.

There was a mean duration of marijuana use of 6.67 years and mean occasion of 3.38 times a day among all participants. No other daily drug use was reported.

All participants showed activation in the nucleus accumbens, also known as the reward region, in response to the marijuana pipe. Differences were found between the two groups for strengths of connections to other areas of the brains.

“We found that the reward network is actually being driven by other areas unrelated to reward, like the areas in memory and attention or emotion,” Filbey said.

Greater activations were found in the orbital frontal cortex and hippocampus among non-dependent participants, suggesting a memory and attention connection, according to the press release. Whereas dependent participants seemed to have more of an emotional connection, as signaled by greater activation in the amygdala and anterior cingulate gyrus.

“Clinicians treating people with problems with marijuana dependence should consider the different processes that trigger the reward response when determining the possible pharmacological or behavioral interventions,” Filbey said.

Disclosure: The study was funded in part by the National Institute on Drug Abuse.