A new article appearing in Experimental and Clinical Psychopharmacology suggests that chronic marijuana use may cause deficits in one’s ability to recognize emotional states in others — one of the hallmarks of what psychologists refer to as emotional intelligence.
“From 2002 to 2017, adult population cannabis use has increased from 10.4% to 15%,” say the researchers led by Alyssa MacKenzie and Anita Cservenka of Oregon State University. “These increases are concerning as a large body of research has reported that cannabis use may have negative impacts on cognitive functioning, learning and memory, processing speed, and attention. Additionally, there is an emerging research area suggesting cannabis use may affect emotion processing.”
To further explore the relationship between marijuana use and emotion processing, the researchers scoured the existing research literature for all studies exploring the link between cannabis use and emotion processing. They found 41 in total (most of which were published in the last five years).
Across the studies, the researchers identified some common themes, such as regular cannabis users demonstrating:
- A lack of responsiveness to emotional stimuli.
- Decreased accuracy and response time when identifying and differentiating emotional states such as happiness, sadness, or anger.
- Decreased neural activity, as measured by brain wave amplitudes, when exposed to emotional stimuli (e.g., happy vs. sad photos).
- A dampening of activity in the prefrontal cortex and medial prefrontal cortex in response to being shown emotional images, as measured by fMRI.
The researchers also found evidence that the sub-components of cannabis, specifically THC and CBD, can influence emotion processing in different ways. For instance, one study found that THC increases anxiety in response to fearful social situations while CBD tends to decrease it.
“To our knowledge, this is one of the first critical review articles focused on an emerging research area of cannabis and emotion processing,” state the authors. “Synthesizing the existing findings in this developing research field is important for future prevention and intervention studies focused on promoting healthy socio-emotional functioning in cannabis users.”
Taken together, this research presents a worrying picture of how regular marijuana use affects emotional intelligence. By blunting the brain’s ability to quickly and accurately process emotional states, regular cannabis users run the risk of weakening their interpersonal relationships. This, according to the researchers, could lead people to use more cannabis as a means to cope with interpersonal problems, thus perpetuating a cycle of marijuana use and emotional distress.
But there is still much to be learned.
“Future studies are needed that categorize cannabis users by duration of use, age of cannabis use initiation, and frequency of daily use,” say the researchers. “Overall, more research on individual differences is needed to determine the effects of sex, polysubstance use, and comorbid psychiatric disorders on socioemotional functioning, and studies should also expand to middle-aged and older adult cannabis users, as the majority of currently published research is limited to adolescents and young adults.”