Strangely, smokers are also less responsive to happy emotions, according to new research.
More and more research on the short-term and long-term effects of smoking cannabis continues to surface, but we still have a long ways to go before the complex biochemistry of the drug is understood.
Lucy Troup, assistant professor of psychology at Colorado State University, and her graduate students set out to investigate how cannabis affects smokers’ abilities to process emotions.
"We're not taking a pro or anti stance; but we just want to know, what does it do? It's really about making sense of it," Troup said in a press release.
The study results, published in the journal PLOS ONE, reveal that cannabis does significantly affect a user’s ability to recognize, process, and empathize with human emotions like happiness, sadness, and anger.
On the bright side, the results also suggest that the brain may have the ability to counteract these effects depending on the way the emotions are detected — either explicitly or implicitly.
The researchers have been conducting experiments for nearly two years using an electroencephalogram (EEG), which measures brain activity. The study consisted of about 70 volunteers who either self-identified as a chronic smoker, a moderate smoker, or a non-smoker of cannabis — the smokers were all legal medical or recreational users under Colorado Amendment 64.
The volunteers were hooked up to an EEG and asked to view faces that depicted four different expressions: neutral, happy, angry, or fearful.
The researchers report that cannabis users showed a greater response to the faces showing negative expressions, particularly angry. On the other hand, cannabis smokers showed less of a response to the positive expressions, like happy faces, than the controls did.
The volunteers were also asked to pay attention to the emotion and “explicitly” identify it. When it came to explicit identification, cannabis smokers and non-smokers were virtually indistinguishable, the researchers say.
However, when they were asked to focus on the sex of the face and later “implicitly” identify the emotion, cannabis users scored much lower than non-users. The researchers report that they also exhibited less of an ability to empathize with the emotions.
The brain’s ability to process emotion is indeed affected by cannabis, the study suggests. It’s easier for smokers to “explicitly” detect an emotion when they’re directed to it, as shown by the results, but “implicitly” processing a deeper level of emotion and empathizing with it is reduced in cannabis users.
Now, Troup is leading a second EEG study focusing on the effects of cannabis on certain mood disorders like depression and anxiety. It’s critical to continue investigating these effects as the drug is slowly but surely becoming more widely legalized for medical and recreational purposes.