A new study conducted by University of Cambridge researchers shows that cannabis users and non-users do not demonstrate a significant difference in motivation. The study explored levels of apathy (loss of motivation) and anhedonia (loss of interest in or pleasure from rewards) and found no difference between cannabis users and non-users in motivation for rewards, pleasure experienced with rewards, or the brain’s activity when seeking rewards. The findings were published in the International Journal of Neuropsychopharmacology.
Participants included 274 adolescent and adult cannabis users who had used cannabis at least weekly over the past three months for an average of four days per week. These individuals completed questionnaires to measure anhedonia, and were asked to rate statements such as “I would enjoy being with family or close friends.” Questionnaires used to measure levels of apathy required participants to rate characteristics such as interest in learning new things or persevering to complete a task. Analysis of questionnaire responses indicated that cannabis users appeared better able to enjoy themselves, and importantly, the researchers found no link between frequency of cannabis use and either apathy or anhedonia in cannabis users.
Roughly over half of the participants engaged in behavioral tasks. The first task assessed physical effort and the second one measured the pleasure gained from rewards. In the first task participants could press specific buttons in order to win points and later exchange them for chocolates or sweets. In the second task, participants were asked to rate how much they wanted to receive of each of three rewards (30 seconds of one of their favorite songs, a piece of chocolate or candy, and a coin) on a scale from ‘do not want at all’ to ‘intensely want’. They evaluated how pleasurable they found the rewards on a scale ranging from significant dislike to an intense like for a reward. The researchers found no significant difference between cannabis users and non-users on either the physical effort task or the real reward pleasure task.
Study author Dr. Will Lawn advocated for more research to study potential associations over a period of time: “There’s been a lot of concern that cannabis use in adolescence might lead to worse outcomes than cannabis use during adulthood. But our study, one of the first to directly compare adolescents and adults who use cannabis, suggests that adolescents are no more vulnerable than adults to the harmful effects of cannabis on motivation, the experience of pleasure, or the brain’s response to reward.” It is important to reduce the stigma of the unmotivated or lazy cannabis user because these presumptions can negatively impact harm reduction efforts.