Use of cannabis at an earlier age was linked to double the chance of being prescribed medications for mental illness.
The study reveals how the first few uses of cannabis change the brain.
Using cannabis just once is enough to change critical areas of the brain, research finds.
Brain scans have revealed changes in the amygdala, an area vital for processing emotions — including fear — after only one or two joints.
Adolescents using the drug for the first time also showed changes to their hippocampus, a structure involved in memory.
Professor Hugh Garavan, study co-author, said:
“Consuming just one or two joints seems to change gray matter volumes in these young adolescents.”
The study included 46 adolescents who had smoked cannabis once or twice before age 14.
There were compared to similar young people who had never touched the drug.
The scans showed changes in the cannabinoid receptors, compared with those who had not used the drug.
Professor Garavan said:
“The implication is that this is potentially a consequence of cannabis use.
You’re changing your brain with just one or two joints.
Most people would likely assume that one or two joints would have no impact on the brain.”
During adolescence the brain typically prunes neurons that are not required.
It is possible that cannabis use during this early period of development can affect this process.
The study was published in The Journal of Neuroscience (Orr et al., 2019).
Many of the same problems linked to cannabis were found in young adults as well as in adolescents.
Regular cannabis use is harmful whether people start in adolescence or later on, new research concludes.
Using cannabis is linked to mental health problems like depression and anxiety, as well as substance misuse problems.
Dr Gary Chan, the study’s first author, said:
“Compared to non-users, regular cannabis users were more likely to engage in high-risk alcohol consumption, smoke tobacco, use other illicit drugs and not be in a relationship at age 35.
These outcomes were more common among those who started using cannabis regularly in adolescence.
They were also at higher risk of depression and less likely to have a paid job.
Overall, regular use of cannabis—more than weekly and especially daily use—was found to have harmful consequences, regardless of the age people began using it.”
The results come from a study of 1,792 Australian high school students who were followed for two decades.
Many of the same problems linked to cannabis were found in young adults as well as in adolescents, the study revealed.
Dr Chan said:
“Two-thirds of people who use cannabis regularly started use in their early 20s.
Because adult-onset is a lot more common than adolescent on-set, most of the harms associated with cannabis are in fact in the group who begin later on.
Those who began regular use as a young adult accounted for the highest proportion of subsequent illicit drug use and tobacco use in the population, and a much higher proportion of high-risk drinking.”
How cannabis use affects the brain
Research on the effects of cannabis on the brain have produced a whole raft of findings — some positive, some negative.
Here are a few:
- Using cannabis frequently is linked to a decline in intelligence.
- However, the short-term intellectual effects of heavy pot use are minimal, a review of 69 studies including 2,100 pot users found. Even the minimal effects quickly disappeared.
- Cannabis is not a ‘safe drug’, as many imagine. Data from more than 120 studies found that marijuana may be harmful for a particular type of vulnerable adolescent, possibly leading to behavioural problems and addiction.
- Using cannabis just once is enough to change critical areas of the brain, one recent study finds.
- Cannabis causes short-term paranoia in some people.
- Regular marijuana users have increased connectivity in their brains, despite having some gray matter loss in areas related to addiction.
- However, long-term alcohol use is more damaging to the brain than long-term cannabis use.
The study was published in the journal Drug and Alcohol Review (Chan et al., 2021).
Research on over 6,000 adolescents reveals how the most popular illicit drug affects IQ.
The second most common medicinal use of cannabis is for mental health problems.
People with a family history of depression were more likely to experience cannabis withdrawal symptoms.
The short-term effects of smoking cannabis on cognition revealed by 69 studies on 2,100 cannabis smokers.
Heavy cannabis use does not have strong negative effects on memory or thinking skills, new research concludes.
The short-term intellectual effects of heavy pot use are minimal, the review of 69 studies including 2,100 pot users found.
Even the minimal effects quickly disappeared.
After abstaining from cannabis for 72 hours, young people’s cognitive skills were back to normal.
Dr J. Cobb Scott, who led the research, said:
“The length of abstinence was associated with how big the effect size was.
We don’t know if three days is a perfect cutoff for this.
We don’t know the maximum point at which abstinence might benefit cognitive functioning.”
The long-term effects of smoking cannabis are still unclear.
Teenagers could be at greater risk of psychosis or other problems as a result of long-term use.
Dr Scott said:
“The more you use cannabis, the more likely you are to have problems with cannabis, just like any other substance.”
People included in the 69 studies were between 18- and 30-years-old.
Smoking cannabis certainly had negative effects on cognition, but they were much smaller than expected.
Dr Scott said:
“It’s considered a small difference between groups, so the clinical significance of that is kind of questionable.
It does raise a question of how big are these differences in a practical sense, and what those differences mean in someone’s life.”
When young people stopped smoking cannabis their memory and thinking skills recovered from the slight deficit.
Dr Scott Krakower, a psychiatrist not involved with the study, said:
“They’re saying basically there’s not maybe as large of a difference in cognitive functioning, but they’re still saying there is potentially some cognitive dysfunction.
Even the smaller changes in cognitive function can still have long-lasting impacts on younger adults and adolescents.”
Dr Scott said:
“It’s important to think about the much longer-term effects of heavy use of cannabis, which this analysis doesn’t tell us that much about.”
The study was published in the journal JAMA Psychiatry (Scott et al., 2018).
One puff of this type of cannabis can help treat the symptoms of depression. Study also tests effect on anxiety and stress.
Psychotic disorders, like schizophrenia, are those that involve becoming detached from reality.
The neurochemical effects of coffee on the brain linked to cannabis by new study.
Coffee affects the same neurotransmitters as cannabis, new research finds.
Drinking four to eight cups of coffee a day decreased the levels of neurotransmitters in the endocannabinoid system.
In other words, coffee has the opposite effect to cannabis (sort of).
Coffee consumption may also help weight loss by having the opposite effect to cannabis: reducing the ‘munchies’, instead of spurring them on.
The endocannabinoid pathway is also important in how the body regulates stress.
The researchers were surprised by the wide-ranging effects of coffee consumption on the human metabolism.
It apparently does way more than just waking us up in the morning.
Dr Marilyn Cornelis, the lead author, said:
“These are entirely new pathways by which coffee might affect health.
Now we want to delve deeper and study how these changes affect the body.”
People in the study abstained for coffee for one month and then consumed four cups in the second month and eight cups in the third month.
Blood tests revealed that coffee consumption reduced activity in the endocannabinoid system, particularly on eight cups per day.
Dr Cornelis said:
“The increased coffee consumption over the two-month span of the trial may have created enough stress to trigger a decrease in metabolites in this system.
It could be our bodies’ adaptation to try to get stress levels back to equilibrium.”
The endocannabinoid system is also involved in many other bodily process, such as cognition, blood pressure, immunity, addiction and sleep.
Dr Cornelis said:
“The endocannabinoid pathways might impact eating behaviors, the classic case being the link between cannabis use and the munchies.”
Coffee is sometimes linked to weight loss, Dr Cornelis said:
“This is often thought to be due to caffeine’s ability to boost fat metabolism or the glucose-regulating effects of polyphenols (plant-derived chemicals).
Our new findings linking coffee to endocannabinoids offer alternative explanations worthy of further study.”
The study was published in the Journal of Internal Medicine (Cornelis et al., 2018).