IT has long been said that the use of ganja (marijuana, cannabis) by children and teenagers may harm their brain since at their age the brain is developing rapidly, and research has shown that ganja use is linked to memory dysfunction.

With recent changes to legislation occurring in some jurisdictions and Jamaica decriminalising the use of two ounces of ganja or less, the potential for the use of ganja has increased exponentially, particularly among the young, with consequential very harmful effects.

In 2015, the American Academy of Pediatrics published a technical report stating that children and adolescents may be harmed when adults have easier access to marijuana for medical and recreational purposes. It further stated that campaigns to decriminalise or legalise marijuana could have the effect of persuading teenagers that marijuana is not dangerous, and this could have a devastating impact on their lifelong health and development.

Driving while intoxicated

Alterations in muscle motor control, coordination, judgement, reaction time, and tracking ability caused by marijuana have all been researched and documented, and these may contribute to injuries and deaths among adolescents and adults if persons drive motor vehicles while being intoxicated by marijuana.

Further, research published in the Journal of the American Medical Association Internal Medicine revealed that ganja impairs memory function that is not age-related, and was instead due to a cumulative exposure to ganja.

New research has now been conducted involving a large prospective study of 3,720 adolescents (teenagers), which represents 76 per cent of all grade seven students attending 31 secondary schools within the greater Montreal area of Canada. For four years, students completed an annual web-based survey in which they provided self-reports of past cannabis use and any symptoms of psychosis. There were no penalties or consequences for reporting cannabis use.

High marijuana use

Once such guarantees were given, students were quite comfortable with reporting their use of cannabis, and they became committed to doing it over the four years of the study. The research found that marijuana use was highly prevalent.

The study, which was conducted by a team of researchers led by a professor of psychiatry at the University of Montreal in Canada and published in the June 2018 edition of JAMA Psychiatry, has revealed that the use of cannabis is harmful as it directly initiates a risk for psychosis illness in teenagers.

The study involved persons aged 13-16 years and revealed statistically positive associations, measured at every point in time, from the use of cannabis to the start of psychosis symptoms occurring up to one year later. The first point of contact made with the teenagers was at the average age of 12.8 years. Twelve months then separated each subsequent assessment of the teenagers.

Increase in psychosis symptoms

In any given year, the use of cannabis predicted an increase in psychosis symptoms a year later. This effect was observed for the entire cohort of teenagers, meaning that all young users faced this risk of psychosis, not just those with a family history or having a biological factor that increased their susceptibility to the effects of cannabis.

The researchers opined that this analysis was more robust than previous research as it assessed the users of cannabis at multiple points in time and examined changes within each person.

Given the widespread pressure towards legalisation of cannabis in some states, the researchers said there is a need to understand whether the use of cannabis has a causal role in the development of psychiatric illness, and this study begins to provide an answer.

Considering this most recent research finding, therefore, all young users of ganja have a risk of developing psychotic illness. Conducting this study to determine causality was especially important in this age group since this is the period when both cannabis use as well as psychosis typically start.

Evidence-based preventive programmes

Evidence-based programmes for the prevention of ganja use currently exist, and so there should be systematic efforts to have them available to high school students in every country. The researchers encouraged governments to dramatically step up their efforts concerning access to these marijuana/cannabis use prevention programmes that are evidence-based, since it has been shown that marijuana use among teenagers is very prevalent.

One survey in the Canadian province of Ontario revealed that about 30 per cent of older high school students were using cannabis. Consequently, governments should seek to forge new innovative policies that would address the high level of use in persons who are under legal age. A great benefit of reducing access to and reducing the demand for ganja among young persons would be a reduction in the risk for major psychiatric conditions.

Dr Derrick Aarons MD, PhD, is a family physician and consultant bioethicist; a specialist in ethical issues in health care, research, and the life sciences; and is the health registrar and head of the health secretariat for the Turks & Caicos Islands.