A study. conducted by neuroscientists Patricia Conrod, Steven Laviolette, Iris Balodis and Jibran Khokhar, has found that cannabis use could lead to cognitive abnormalities, inhibitory control and impairments in working memory in an adolescent brain.
The research, showcased at the 13th Annual Canadian Neuroscience Meeting, was broken up into segments for better understanding.
Dr. Patricia Conrod, at Université de Montréal, studied 3,826 7th grade students entering high school in 2012 and 2013 in the Greater Montreal region. They were assessed annually for a period of 4 years on cannabis and alcohol use and their cognitive function was evaluated using computerized cognitive tests.
Conrod and her fellow researchers found cannabis use to be linked to impairments in working memory and inhibitory control (self-control). Furthermore, the use of the drug was also linked to deficits in perceptual reasoning and memory recall.
Dr. Steven Laviolette, who studied the effects of delta-9-tetrahydrocannabinol or THC, the psychoactive compound in cannabis, in rodent animal models, demonstrated that adolescent exposure to tetrahydrocannabinol or THC induces changes inside a specific region of the brain called the prefrontal cortex (PFC) and in a brain circuit, the mesolimbic pathway. These changes closely resemble the abnormalities observed in Schizophrenia patients.
The team, however, was happy to find that the drugs that restore normal PFC function in early adulthood could reverse the repercussions of THC exposure in adolescents.
Interestingly, it was also seen that co-administering THC with drugs that prevent the THC-induced disruption in brain signaling pathways hindered the development of schizophrenia-like effects.
Dr. Iris Balodis, from McMaster University, looked at the mechanisms which motivate individuals to act and make decisions that can go against a person’s best interest, as generally witnessed in people suffering from addiction. For this, he created an activity where subjects (both cannabis users and non-users) could choose between an easy and a hard task, which, when completed successfully, will fetch them cash rewards – more cash for the harder tasks.
During the activity, Balodis and her team looked at the differences in activity in different brain regions by functional magnetic resonance imaging. Initial findings showed that there are differences in encoding the value of the reward (money) and of the effort cost (amount of work done) in individuals addicted to marijuana relative to healthy controls.