Tune into CCSA's Facebook page February 26th at 8am EST for The Evidence on #Edibles, a special Facebook Live event.
CCSA will be live streaming a panel discussion about Canada's upcoming cannabis edible legalisation.
A recent study, published in the Journal of Addiction, has examined the association of cannabis use, cannabis use disorder and symptoms of psychosis, depression and anxiety in an adolescent and adult sample. The researchers also examined the differences in these associations and the onset of cannabis use and sex differences.
Highlights of results:
These results contribute to the body of research that has shown associations between cannabis use and increase the risk of mental health issues in adolescents and adult populations. It is essential that individuals are made aware of these links, so their decisions are appropriately informed.
Pre-existing mental disorders increases the risk of developing SUD.
Relatively little is known about factors that may lead to the development of a substance use disorder (SUD), across a range of drug classes. This study aimed to identify factors that predict the likelihood of transition from use to SUD and the speed with which this may occur at the population level, with a focus on the impact of pre-existing mental disorders.
Data were collected as part of the 2007 Australian National Survey of Mental Health and Wellbeing, a nationally representative survey of 8841 Australian adults. A series of discrete time survival analyses were undertaken on data pertaining to the age of onset of use and symptoms of use disorder, for alcohol, cannabis, sedatives, stimulants, and opioids, as well as the impact of pre-existing mood and anxiety disorders on the likelihood of developing a SUD.
Lifetime cumulative probability estimates indicated that 50.4% of stimulant, 46.6% of opioid, 39% of sedative, 37.5% of alcohol, and 34.1% of cannabis users would develop a SUD on those substances, within an estimated 14, 12, 8, 30, and 23 years after onset respectively. Pre-existing mental disorders were significantly associated with increased risk of developing a SUD for alcohol, cannabis and stimulant use disorder.
The relative speed associated with the transition from use to SUD emphasizes the narrow window of time available to intervene, underscoring the urgency of early identification of mental health conditions and the timely provision of appropriate evidence-based interventions, which could potentially prevent the development of secondary SUDs.
Cannabis use is observationally associated with an increased risk of schizophrenia, but whether the relationship is causal is not known. Using a genetic approach, we took 10 independent genetic variants previously identified to associate with cannabis use in 32 330 individuals to determine the nature of the association between cannabis use and risk of schizophrenia. Genetic variants were employed as instruments to recapitulate a randomized controlled trial involving two groups (cannabis users vs nonusers) to estimate the causal effect of cannabis use on risk of schizophrenia in 34 241 cases and 45 604 controls from predominantly European descent. Genetically-derived estimates were compared with a meta-analysis of observational studies reporting ever use of cannabis and risk of schizophrenia or related disorders. Based on the genetic approach, use of cannabis was associated with increased risk of schizophrenia (odds ratio (OR) of schizophrenia for users vs nonusers of cannabis: 1.37; 95% confidence interval (CI), 1.09–1.67; P-value=0.007). The corresponding estimate from observational analysis was 1.43 (95% CI, 1.19–1.67; P-value for heterogeneity =0.76). The genetic markers did not show evidence of pleiotropic effects and accounting for tobacco exposure did not alter the association (OR of schizophrenia for users vs nonusers of cannabis, adjusted for ever vs never smoker: 1.41; 95% CI, 1.09–1.83). This adds to the substantial evidence base that has previously identified cannabis use to associate with increased risk of schizophrenia, by suggesting that the relationship is causal. Such robust evidence may inform public health messages about cannabis use, especially regarding its potential mental health consequences.
With legalization of recreational cannabis looming, The Schizophrenia Society of Canada wants young people to understand the risks of using the drug.
The society has launched a new website to increase awareness.
‘Cannabis and Psychosis: Explore the Link’ aims to provide comprehensive and accessible information to help youth better understand the issue.
The website states: “Regular cannabis use impacts the development of a chronic life-long psychotic disorder in at risk individuals and is associated with an earlier age of onset of psychosis. However, there is currently no way to identify who is at risk of developing psychosis with cannabis use.”
“Specifically the website is geared towards cannabis and it is saying that there is a link, a definite link, between the use of cannabis and the development of psychosis that could lead to full-blown Schizophrenia,” said Schizophrenia Society of Canada CEO Chris Summerville. “There is 30 years of research, especially in the last 10 years, demonstrating that there is a clear link between cannabis and psychosis.”
Summerville said using marijuana can affect the part of the brain critical to judging, reasoning, and planning.
“When you take THC, which creates the rush from cannabis, that THC interferes with the neurotransmitters and receptors and your endocannabinoid system of your free frontal cortex,” said Summerville. “And that’s especially true during the first 25 years of life.”
“That’s the connection and that’s the connection in research and that’s what most people, even service providers, don’t understand or have not learned about that. The youth brain, or the emerging adult brain, is very vulnerable to cannabis because it’s developing its own cannabis, endocannabinoid system and THC content today is 28 per cent whereas during the hippy movement in the sixties and seventies the THC content was 1.25 per cent.”
“What we’re dealing with today is about 25 times stronger.”
The Schizophrenia Society of Canada said the website was made with support from the Substance Use and Addictions Program of Health Canada and the Canadian Centre for Substance Use and Addictions.
A note on the website said the opinions and interpretations contained in the site are those of author and do not necessarily reflect those of the Government of Canada.
It has been suggested that cannabis use increases risk of driving collisions through affecting braking and choice reaction time; causing impairment of lane position, disrupting head-way and dynamic tracking; distorting time perception; reducing divided and sustained attention; and increasing caution.
A recent Canadian study, published just two days before cannabis was legalized across the country, investigated the impact of cannabis use on driving performance in young recreational users.
The study investigated 45 recreational marijuana users between the ages of 18 and 24. Participant’s driving reflexes were tested in a driving simulator with no cannabis in their system, and then one, three and five hours after inhalation of a standard 100-mg dose of cannabis through a vaporizer (a typical joint is 300-500 mg of dried cannabis).
Participants were also asked to rate perceived driving ability and safety at each stage of the experiment.
Results found that although cannabis use made no significant difference when it came to simple driving actions such as braking, steering and maintaining a steady speed, complex driving-related performance, such as reacting to avoid sudden obstacles, was affected at all time points after cannabis use.
Findings from the self-reported driving ability and driving safety showed that participants in this trial did not perceive themselves to be as safe to drive at 1, 3 and even 5 hours after cannabis use.
Overall the research highlights the importance of adhering to the guidelines on driving after using cannabis and waiting at least 6 hours before getting behind a wheel.
The controversial subject of cannabis legalisation has led to the increased urgency in understanding the full health and social implications of the drug use. Cannabis use is particularly prevalent amongst adolescence - a period of time where young people are going through significant neural development. Cannabis use is thought to affect normal neuromaturation, increasing the risk of cognitive impairment.
A recent study, published in the Journal of Clinical Psychiatry, has investigated whether young people can recover from drug-induced cognitive impairment by stopping cannabis use for an extended period of time.
The study analysed 88 young people, aged between 16 and 25, who described using cannabis on a weekly basis. The participants were grouped into those who were asked to abstain using cannabis for one month and those who were allowed to continue use. The participants were also asked to complete multiple cognitive tests over the course of the month.
Results found that memory (specifically declarative memory - the ability to learn and recall new information) improved only among the group who stopped using marijuana for a month. The researchers concluded that cannabis use disrupts areas of the brain that are particularly involved in the memory-learning network and that abstaining from cannabis allows for more efficient processing of information.
This research provides evidence that adolescents may experience improvements in their capacity to learn and recall new information when they stop using cannabis.
