For years studies have purported to show that marijuana use has a wide range of ill health effects, but recent research has shown positive results in the field of medicinal use. How can that be?
Marijuana, also known as cannabis, comes from the Cannabis sativa or Cannabis indica plant. The plant contains the mind-altering chemical THC that acts on specific brain cell receptors that ordinarily react to natural THC-like chemicals. These natural chemicals play a large role in brain development and function.
Marijuana is a psychoactive drug. Its ‘high’ can last up to 12 hours and can make people feel more relaxed, alter the senses and cause time distortion.
Unlike other illegal drugs, no one has ever been reported dead from a marijuana overdose.
Marijuana is not classed as addictive however it can lead to ‘substance use disorder’. Historical research has reported negative short-term health effects to include anxiety or paranoia and impaired thinking, judgement, co-ordination and memory.
Negative long-term effects have said to include breathing problems like coughing , excess mucus, bronchitis, and worsening of conditions like schizophrenia, asthma and cystic fibrosis. Marijuana use during pregnancy can also harm a baby’s brain development.
In the Ministry of Health’s Cannabis Use 2012/13: New Zealand Health Survey it found that eight percent of cannabis users reported a time in the last 12 months that cannabis use had a harmful effect on their mental health. Younger cannabis users were more affected, with reported harm to mental health decreasing markedly by age 55 plus.
On the other hand, further, more recent studies have shown marijuana can provide significant relief for pain and nausea, as well as well as helping to control epilepsy. It is not yet proven if marijuana is linked to lung cancer, but according to a study published in Journal of the American Medical Association in January 2012, marijuana does not impair lung function and can even increase lung capacity.
Another study, by Harvard, into the health effects of recreational and medical use concluded that, “Early research shows cannabidiol and its derivatives hold potential promise in additional conditions like drug-resistant epilepsy and some psychiatric disorders (e.g., anxiety, substance use disorders, schizophrenia, and psychosis).”
The drug has been steadily growing in popularity for medical applications and is now legal for medicinal purposes in at least 20 countries worldwide.
So here we are: some scientific studies conclude that marijuana use is harmful, others claim it to be a medical miracle. A recently-concluded New Zealand longitudinal study, conducted in part by researchers at Duke University, appears to finally clear the air.
The study is perhaps the most comprehensive into the subject yet: it monitored a cohort of 1037 individuals, born in Dunedin in 1972 and 1973, over 38 years, testing whether cannabis use from age 13 to 38 was associated with health effects at 38. It assessed frequency of cannabis use and cannabis dependence at ages 18, 21, 26, 32 and 38 years.
It found that the people who started smoking marijuana heavily in their teens, and had an ongoing marijuana use disorder, lost an average of eight IQ points between ages 13 and 38. The lost mental abilities didn’t fully return in those who quit marijuana as adults.
Interestingly, those who started smoking marijuana as adults didn’t show notable IQ declines, indicating that heavy or long term marijuana users only suffer poor mental abilities if they began using before their brain had developed in full.
It concluded that “Cannabis use for up to 20 years is associated with periodontal disease but is not associated with other physical health problems in early midlife”.
This is not the only notable New Zealand study on the matter. The World Health Organisation in 1998 released a report that agreed with the New Zealand Ministry of Health’s report Cannabis: the public health issues 1995-1996 in acknowledging that the consumption of alcohol and tobacco are more harmful than the use of cannabis.
Neurosurgeon and CNN’s chief medical correspondent, Sanjay Gupta, offers further explanation into the division on the matter.
In 2009 Gupta penned a TIME Magazine article entitled ‘Why I would vote No on Pot’, but recently while in the process of making his documentary Weed, he changed his stance from being anti- to pro-legalisation of cannabis in the medical field.
“We have been terribly and systematically misled for nearly 70 years in the United States, and I apologise for my own role in that,” he told CNN in an interview.
He found in a search of medical studies from the past year that only six percent investigated potential benefits of the drug, rather than its harms.
“It [marijuana] doesn’t have a high potential for abuse, and there are very legitimate medical applications. In fact, sometimes marijuana is the only thing that works,” he wrote.
In another recent study on twins, those who used marijuana showed a significant decline in general knowledge and in verbal ability, equivalent to four IQ points, between the preteen years and early adulthood. But no predictable difference was found between twins when one used marijuana and the other didn’t.
This suggests that the IQ decline in marijuana users may be caused by something other than marijuana, such as shared familial factors, for example, genetics and family environment.
In medicinal-specific studies, researchers have learnt there are at least two active chemicals in marijuana that they think have medicinal application. Those are cannabidiol (CBD) — which seems to impact the brain without a high — and tetrahydrocannabinol (THC) — which has pain relieving properties.
Public opinion is congruent with recent, further research showing positive results in the field of medicinal marijuana.
The New Zealand Drug Foundation’s August 2017 poll showed support is growing for a cannabis law reform.
The poll was conducted by National Party pollsters Curia and showed that overall, 81 percent of voters supported allowing medical cannabis for patients with terminal illnesses.
It remains a somewhat divisive topic for New Zealand leaders, however. At the first leaders’ debate, Labour leader Jacinda Arden took all of three seconds to say her party would absolutely look at legalising marijuana for medicinal use.
Prime Minister Bill English, who has up until now claimed he’s happy with New Zealand’s current cannabis laws, used his full 30 seconds to state that National would be happy with more liberal access to medicinal marijuana, but in the form of controlled cannabinoid products that have passed clinical trials, just as every other government-approved drug must do.
One thing is for certain: comprehensive research continues on the matter and will only add depth to a growing portfolio of studies offering accurate and insightful results.
By Lydia Truesdale