Dr. Lucy Troup and her colleagues looked at 73 people over the course of two years to see the impacts of cannabis use on emotional processing (by the end of the study the sample was down to 70 participants). All of the volunteers were asked if they were a heavy cannabis user, a moderate user, or a non-user before being asked to strap on an electroencephalogram (EEG) to measure their brain activity.
Though EEGs can measure a wide range of brain activity in this study the researchers used it to observe P3 event-related potentials (ERPs), which are a measure of the activity taking place in the cerebral cortex in direct response to a specific event (whether sensory, cognitive, or motor), an event like being shown a picture. P3 is of particular interest here because, it has been “consistently linked to emotion processing.”
While the EEG was attached, the researchers elicited a P3 response by showing participants various pictures of faces depicting four emotions: neutral, happy, fearful and angry (the pictures came from the Radboud Faces Database). Cannabis users were shown to display an increased P3 response to negative expressions, particularly angry faces, interestingly they were shown to have a decreased P3 response to positive (happy) expressions and no changes regarding neutral expressions.
Dr. Troup and her colleagues noted that “these effects appear to increase with those participants that self-reported the highest levels of cannabis consumption,” possibly indicating a relationship between the amount of cannabis used and the degree of impairment. While some differences were observed where cannabis users were asked to implicitly identify the emotion depicted, little difference was observed in explicit attempts to identify emotions. This distinction between implicit and explicit emotional processing is interesting and worth exploring with further research.
Dr. Troup clearly anticipated backlash to the study, and added the caveat that her team was “ not taking a pro or anti stance” towards cannabis and “just want to know, what does it do,” stressing that it was “really about making sense of it.”
Similarities to Autism
“We found that when you ask a cannabis user to think about other people’s emotions and relate to them, it’s harder for them,” Dr. Troup told VICE news about her study. “That inability to empathize would be a parallel to autistic-like behaviors.”
She added that, after releasing her study, she has, “been approached by a number of researchers who are very interested in the use of cannabis to treat autism and if the two are related or causal.” For Dr. Troup, “this is something to think about.” According to VICE, “Dr. Troup infers that weed inhibits a person’s ability to intuitively identify emotions when they’re not explicitly focusing on them” and that has similarities to autism.
Dr. Frank Lucido is a very knowledgeable medical cannabis doctor located in Berkeley, California, who sees dozens of pediatric patients who use CBD to treat epilepsy and other conditions, including autism. Dr. Lucido believes that “THC, and possibly also THCA have their places, especially with some of the behavioral issues of autism, which is a common co-factor in many of the seizure disorders I have seen.” That said, Dr. Lucido advises that patients be “titrated up to near the ‘theoretical maximum’ dose of CBD and evaluate the effects” before “adding other variables, such as other cannabinoids,” which could make it harder to know which cannabinoid is giving you the deserved effects. Dr. Allen Frankel is an LA-area doctor who, like Dr. Lucido, sees numerous pediatric epileptic patients, many are on the autistic spectrum. Dr. Frankel has similar advise to Dr. Lucido, “I recommend starting slow and low, with a gradual build up. I add THC if they aren’t seeing any benefits or if they are on the autistic spectrum to help control outbursts.” Based off the dosing advice of two experts, it would seem that THC, and potentially THCA, in combination with CBD, could be potential treatments to control outbursts and other behaviors associated with autism.
I asked Dr. Troup to give me her view on cannabis dosing for autism based off what she observed in her study.
“There is a great deal of research both animal and human that points to THC having a negative impact on developing brains,” she said. “I would argue coupled with my findings and as yet unpublished work in my lab that THC would not necessarily be a sensible phytocannbiniod to administer for individuals on the Autism Spectrum. CBD is another story and has its own complexities associated with it.”
When asked if anyone in the study was known to be on the autistic spectrum, Dr. Troup replied, “we did not screen for Autism and are developing a follow up study that will include a screen for the disorder.” Dr. Troup stressed that it was not just autism of relevance to her team, they want to look for “relationships between casual, chronic and non-users in respect” to depression, anxiety and PTSD.
In her VICE interview, Dr. Troup speculated that many cannabis users may be intentionally, or inadvertently, self-medicating to regulate mood disorders they may not even know they have; she also recognized that it could have plenty of harms as well as benefits.
“In some cases, weed could be deadening down negative emotions, but it could be the other way,” she said. “Because [some cannabis users] aren’t able to process negative emotions it can impact them socially. They can’t recognize when others are angry. They can’t recognize when they’re angry.”
Dr. Troup understands that “there’s so much individual variability” in response to cannabis; everyone is different and the same 50mg of THC or CBD will affect 50 people differently. Like most studies on medical cannabis, Dr. Troup and her colleagues did not attempt to record if participants were using THC-rich or CBD-rich cannabis, though at least her study did record dosing amounts to report a dose-dependent relationship. As the vast majority of the medical cannabis market, and virtually all of the recreational market, is THC-rich we should assume that the vast majority of participants were using THC-rich cannabis, not CBD, so any effects noted by this study only apply to users of THC-rich cannabis. When I followed up with Dr. Troup about this her reply was that “Colorado has only recently introduced legislation requiring the testing of cannabis (HB 15-1283) and then it is only for recreational use not medicinal.” She added that, without accurate lab testing, “most users especially casual users are unaware of the phytocannabiniod content of their product and the same goes for medical users in a lot of cases.”
Could Something Other Than Cannabis Be the Cause?
Dr. Troup herself is still a skeptic and recognizes that “the million dollar question is, does cannabis exacerbate these disorders or is this deficit a positive way to ‘cope’ with emotional dysfunction?” Expanding on this she discusses the inconsistencies seen in previous research, “for every well designed study that supports its use therapeutically there are studies that suggest it is not beneficial and could in fact exacerbate health issues.”
One way to tell if cannabis use caused autistic behaviors to increase would be to see if rates of autism had gone up in America over the past half a decade, corresponding to the 5.8 pecent increase seen in the Substance Abuse and Mental Health Services Administration (SAMHSA). With cannabis use reported at the highest percent ever since Gallup began asking the question back in 1969, one would anticipate seeing record rates of autism in America. Instead, the Centers for Disease Control and Prevention (CDC) just released a report showing that the autism rate appears unchanged from two years ago, despite four states and Washington DC now having recreational legalization on top of the two dozen medical states. The CDC cautions that this doesn’t mean that the rate has stabilized, but for our purposes (exploring if cannabis use is causally linked to autistic-like behavior), it makes for a compelling point.
While this study was widely reported as showing that cannabis use worsened emotional processing and reduced empathy, is that what was actually studied? What the researchers really observed was cannabis user’s abilities to pay attention to faces and accurately report their subjective opinion of what someone else’s subjective opinion of an angry, happy, fearful, or neutral face looks like. Not everyone looks the same when they are emoting; everyone displays emotion in their own unique fashion and often wires can get crossed, even for people who are sober, especially if they belong to different cultures. When asked about this Dr. Troup replied “you are correct about emotion being processed and expressed differently in other cultures” which is why “Asian countries use different databases [than Radboud].”
The Radboud Faces Database is based out of the Netherlands, and features photos of only “39 Caucasian Dutch adults (19 female), and 10 Caucasian Dutch children (6 female)”; meaning every face in the Radboud database is ethnically a white European. These faces were then shown to Americans, who may or may not have white European ancestry. Those American’s subjective views of Dutch emoting was then used as the basis to determine if cannabis reduces one’s ability to empathize and accurately detect emotions. As there is a clear western bias in the Radboud database itself, specifically a white European bias, this bias appears to cast some doubt over the study’s findings.
When I asked Dr. Troup about this apparent bias she replied that while “ it is validated on [only] white Caucasian faces [it] has been normed on many many hundreds of studies,” she added that “here in Colorado it is a very good fit. Our student population and the community is predominantly white American.” Though the race may match, the culture between the Netherlands and Colorado is quite different and it will take another study to see if these findings hold up when accounting for the myriad of factors ignored by this pilot study. On top of that, recent research by psychologist Lisa Barrett calls into question the central premise of the 40-year-old theory of universal emotion upon which the Radboud database was created; perhaps the researchers should have used another database, like the multi-racial MR2.
Dr. Troup agrees that we need more research to know for certain, “from the lowest levels of understanding cannabis effects at the cellular level right up to its effects at the psychosocial level.” Her research isn’t meant to “glorify or demonize,” she is “trying very hard with my work to produce a sensible, ecologically valid approach to understanding cannabis and its effects.” In the month since Dr. Troup’s study was published, a new emotional constant has been discovered that future research on cannabis and emotion could use, instead of culturally biased emotions. The ‘Not Face’ has been demonstrated to be “identical for native speakers of English, Spanish, Mandarin Chinese and American Sign Language (ASL).”
It is also worth noting that empathy is not purely conveyed through facial expressions, empathy is a very deep emotional connection between two or more people that uses the full gamut of human communication, including verbal components, tonal elements, and a copious amount of body language. My emphasis is added to the word body because body language requires a person to see the entire body, their posture and mannerisms; a whole lot more than just a snapshot of a face.
To have people view snapshots of faces and to then extrapolate on their abilities to empathize with those caricature faces would be like being in Plato’s Cave and drawing conclusions on the world outside based solely on shadow-puppets on the wall. With the current federal embargo on cannabis research, unfortunately all we are left with is shadow-puppets and glimpses at what cannabis really does.
Does cannabis change the way you interact with others? Tell us how.