Cannabis users are less likely to lack motivation than non-users: study breaks ‘stoner’ stereotype

Overview: Cannabis users showed no difference in motivation, pleasure from rewards, or reward-seeking brain responses compared to non-users.

sauce: Cambridge University

Adult and adolescent cannabis users are just as likely to lack motivation or enjoy life’s pleasures as non-users, new research shows, often portrayed in the media It suggests that stereotypes have no scientific basis.

Cannabis users also show no difference in motivation for rewards, pleasure derived from rewards, or brain responses when seeking rewards compared to non-users.

Cannabis is the third most commonly used controlled substance in the world, after alcohol and nicotine. Nearly one in five of her 15-year-olds in the UK (19%) had used cannabis in the last 12 months, according to the NHS Digital Lifestyle Team’s 2018 report, and by 2020 The National Institute on Drug Abuse reported that percentage. The United States makes him 28% when he is 15-16 years old.

A common stereotype for cannabis users is the “stoner.” Think Jesse Pinkman from “Breaking Bad,” the guy from “The Big Lebowski,” and most recently Argyle from “Stranger Things.” These are individuals commonly portrayed as lazy and apathetic.

At the same time, there is considerable concern about the potential effects of cannabis use on the developing brain, and cannabis use during adolescence can have detrimental effects at key times in an individual’s life.

A team led by scientists from the Institute of Psychiatry, Psychology and Neuroscience at UCL, the University of Cambridge and King’s College London found that cannabis users experienced higher levels of apathy (loss of motivation) and anhedonia (loss of interest). A study was conducted to investigate whether the or pleasure from rewards) compared to controls, and unwillingness to make physical effort to receive rewards. This survey was part of the CannTEEN survey.

This result was published in the International Journal of neuropsychopharmacology.

The team recruited 274 adolescent and adult cannabis users who had used cannabis at least once a week, an average of four days per week, during the past three months, and matched them with non-users of the same age and gender.

Participants responded to a questionnaire to measure anhedonia, and were asked to rate opinions such as “I enjoy being with my family and close friends.” They also completed a questionnaire to measure their level of apathy, asking them to rate characteristics such as how interested they are in learning new things and how likely they are to complete a task.

Cannabis users scored slightly lower on anhedonia than non-users, in other words they appeared to enjoy themselves more, but there was no significant difference in terms of apathy. Researchers also found no association between frequency of cannabis use and apathy or anhedonia among those who used cannabis.

Dr. Martin Scumlien, Cambridge University Psychiatry Candidate, said: I used cannabis every day. This is the exact opposite of the typical depiction you see on TV and in movies. ”

In general, adolescents tended to score higher than adults on anhedonia and apathy in both user and non-user groups, but cannabis use did not widen this difference. .

Dr Will Roan, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, said:

“However, our study, one of the first studies to directly compare cannabis-using adolescents and adults, suggests that adolescents may be more affected by the detrimental effects of cannabis on their brain responses to motivation, pleasure experiences, or rewards.” This suggests that they are less vulnerable than adults to

“In fact, cannabis generally appears to have no, or at best weak, associations with these results. We need research.”

Just over half of the participants also performed many behavioral tasks. These first rated physical effort. Participants were given the option to press a button to earn points, which they could later take home in exchange for chocolates and sweets.

There were 3 difficulty levels and 3 reward levels. More difficult exams required faster button presses. At each trial, participants can choose to accept or decline the offer. Points will only accrue when the trial is approved and completed.

In the second task, participants were first presented with three rewards (30 seconds of their favorite song, one piece of chocolate or candy, and a £1 coin) to measure how much pleasure they received from the rewards. was expressed on a scale from “not wanting at all” to “strongly wanting”. They were then asked to take each reward in turn and rate how much they enjoyed it on a scale from ‘not at all’ to ‘very much’.

The researchers found no difference between users and non-users, or between age groups, on either the physical effort task or the actual reward pleasure task, and found no difference, Or confirmed evidence from other studies that there is little difference.

“We’re so used to seeing ‘lazy stoners’ on screen that we don’t ask if they’re an accurate representation of cannabis users,” Scumlien said. This in itself is the laziness stereotype, suggesting that people who use cannabis are no more likely to be unmotivated or lazy than those who don’t.

“Unfair assumptions can be stigmatizing and can get in the way of messages about harm reduction. I have.”

Earlier this year, the team published a study using functional magnetic resonance imaging (fMRI) to examine brain activity in the same participants participating in a brain-imaging task that measures reward processing. The task involved participants viewing an orange or blue square on the scanner. Orange squares lead to monetary reward after delay if the participant responds.

The researchers used this setting to investigate how the brain responds to reward, with a particular focus on the ventral striatum, a key region of the brain’s reward system. They found no relationship between activity in the area and cannabis use. This suggests that cannabis users have a reward system similar to that of non-users.

Barbara Sahakian, Professor of Psychiatry at the University of Cambridge, said: “Our evidence suggests that cannabis use does not appear to affect the motivation of recreational users.

“Participants in our study included users who took cannabis daily and were less likely to lack motivation. As can be seen, we cannot rule out the possibility that more use will have an impact.

“Until future research studies follow adolescent users from inception through adolescence and combine motivation and brain imaging measurements, we conclude that regular cannabis use does not adversely affect motivation and the developing brain. You cannot.”

About this motivation and cannabis research news

author: press office
sauce: Cambridge University
contact: Press Office – University of Cambridge
image: image is public domain

Original research: open access.
“Anhedonia, apathy, pleasure, and effort-based decision making in adult and adolescent cannabis users and managers ” Martine Skumlien et al. International Journal of Neuropsychopharmacology

open access.
“Neural responses to reward expectations and feedback in adult and adolescent cannabis users and controls.” Martine Skumlien et al. neuropsychopharmacology

Overview

See also

Anhedonia, apathy, pleasure, and effort-based decision making in adult and adolescent cannabis users and managers

Background

Cannabis use may be associated with anhedonia and apathy. However, previous studies have had mixed results, and few studies have examined associations between cannabis use and specific reward subprocesses. Adolescents may be more susceptible to the harmful effects of cannabis than adults. This study explores (1) the associations between non-acute cannabis use and effort-based decision-making for apathy, anhedonia, pleasure, and reward, and (2) whether these relationships are moderated by age group. Did.

method

We used data from the “CannTeen” study. Participants were 274 adult (ages 26-29) and adolescents (ages 16-17) cannabis users (use 1-7 days per week over the past 3 months) and gender- and age-matched controls. was. Anhedonia was assessed using the Snaith-Hamilton Pleasure Scale (n=274), and apathy was measured with the Apathy Evaluation Scale.n=215). Effort-based decision-making for reward was measured in a physical effort task (n=139), and subjective reward desires and preferences were measured with the novel Real Reward Pleasure task (n=137).

result

Controls had higher levels of anhedonia than cannabis users (debt_1,258=5.35, p=.02,h_p²=.02). There were no other significant effects of user group and no significant user group*age group interaction.The null finding was supported by after Bayesian analysis.

Conclusion

Our results show that cannabis use with a frequency of 3-4 days per week is not associated with apathy, effort-based decision-making for rewards, reward cravings, or reward preferences in adults or adolescents. suggests. Cannabis users reported less anhedonia than controls, despite a smaller effect size. These findings are not consistent with the hypothesis that non-acute cannabis use is associated with motivation.

Overview

Neural responses to reward expectations and feedback in adult and adolescent cannabis users and controls.

Chronic drug use can alter the brain’s reward system, but the extant literature on neural correlates of long-term cannabis use and reward processing shows mixed results. Adolescents may be more susceptible to the adverse effects of cannabis than adults. However, this has not been investigated for reward processing.

Rewards in cannabis in 125 adults (ages 26-29) and adolescents (ages 16-17) in the largest functional magnetic resonance imaging study of reward processing and cannabis use to date, as part of the “CannTeen” study. surveyed predictions and feedback. User (her 1–7 days of cannabis use per week) and gender- and age-matched controls using a monetary incentive delay task. Responses dependent on blood oxygen levels were analyzed by region of interest (ROI) analysis in the bilateral ventral striatum for reward prediction, right ventral striatum and left ventromedial prefrontal cortex for feedback, and exploratory whole-brain investigated using analytics.

The results showed no effect of user group or user group × age group during reward prediction or feedback on the predefined ROI. These null findings were corroborated by post hoc Bayesian analysis. However, in whole-brain analyses, cannabis users showed greater feedback activity in the prefrontal and inferior parietal cortices compared to controls.

In conclusion, cannabis users and controls exhibited similar neural responses during reward anticipation and in hypothetical reward-related areas during reward feedback. A whole-brain analysis revealed preliminary evidence for greater frontoparietal activity in cannabis users during feedback. Adolescents did not show increased vulnerability compared to adults.

Overall, adolescent and adult cannabis users appear to be immune to reward expectations and feedback processing, although future longitudinal studies are needed to confirm this.