People do drugs because it makes them feel good. Or, at the very least, less bad. The illicit drug trade is fueled by the pursuit of pleasure, which, as a fundamental part of human nature, is very hard to impede. Scientists trying to hack this system, however, have learned that addictive drugs aren’t always optimally pleasurable. As they report in a study on cocaine and heroin published Monday in JNeurosci, sometimes pleasure depends on a place.

In the small study, the team of researchers show, using brain scans and surveys from drug users, that taking heroin and cocaine is more pleasurable if they’re taken in specific settings. The team, led by Silvana De Pirro, Ph.D., of the Sussex Addiction Research and Intervention Centre, based their experiment on the fairly intuitive “mismatch hypothesis,” which says that a drug won’t feel as pleasurable if it’s used in a setting that’s at odds with the function of the drug. By this logic, it wouldn’t be as fun to take heroin, a sedative, in a high-energy environment, such as a club, and it wouldn’t be as fun to take the stimulant cocaine somewhere boring, like a house. Sure enough, a pair of experiments on 73 people addicted to both cocaine and heroin showed that pleasure was definitely dependent on setting.

pleasure linked to heroin and cocaine use is setting dependent
The feelings associated with heroin and cocaine use varied by setting.

The 53 people who took part in the first experiment reported, through established psychology questionnaires, how enjoyable and arousing their experiences with cocaine and heroin were both inside and outside of the home. In the second experiment, the team guided 20 participants in a visualization task in which they were asked to imagine themselves doing heroin and cocaine in both at-home and outside-of-home settings while inside an MRI machine, which scanned their brain activity while they did so.

Both the questionnaires and the brain imaging experiment showed that 89.1 percent of heroin users had pleasurable experiences doing heroin at home and that about 50 percent of cocaine users reported either pleasurable or mixed-state feelings doing cocaine at home. “Simply moving from one setting to another significantly decreased heroin pleasure but increased cocaine pleasure, and vice versa,” the authors write. Corroborating these findings, the parts of the brain that were active as the participants imagined using drugs were previously shown to be involved in processing reward linked to drug use.

By showing the settings in which users find drug use most pleasurable, the study points out the key areas users need to avoid if they’re in rehab for addiction. “Considering the interaction between drug type and location could help to prevent relapse,” said De Pirro in a statement published Monday.

“Governments should adapt policies to ensure that therapies take into account the impact of the environmental factors on the risk of relapsing, and on its role in supporting recovery from addiction.”