JAMAICA decriminalised the use of two ounces or less of ganja last year in an effort to prevent people getting a criminal record for its use. Unfortunately, this action was not preceded by the massive public education campaign required to fully inform the nation about the possible harms ganja causes to some people, and to youths in particular.

Instead, its commercial and medicinal benefits were the only issues being heralded in the media. It should not have surprised the nation, therefore, when two weeks ago, the Minister of Health Dr Christopher Tufton revealed in Parliament that there had been a 50 per cent increase in the number of students being treated for the harmful effects of ganja.

FORESEEABLE HARM TO CHILDREN

This was foreseeable, since in an article in the Sunday Observer of March 1, 2014, entitled ‘Caution in decriminalising ganja: We must protect our children’, Jamaica was informed of a study published in the medical journalAnnals of Emergency Medicine, which showed that the incidence of marijuana (ganja) exposure in children had increased between 2005 and 2011 in those states in the United States of America that had passed marijuana legislation.

The data had been gathered by the America Association of Poison Control Centers National Poison Data System, and it showed that while the rate in other states with no marijuana legislation remained unchanged, there was a 30 per cent increase of unintentional marijuana exposure among children in states that had decriminalised the use of marijuana.

Symptoms of children exposed to marijuana were varied, but were mainly neurologic (affecting the nervous system). Further, a little discussed fact is that ganja affects short-term memory, thereby inhibiting children and adolescents’ ability to learn. Learning involves information (knowledge) being first stored in short-term memory within the brain for a couple of days, before it is transferred to the long-term memory compartment for permanent storage and recall. Ganja inhibits the functioning of short-term memory, and so impairs learning in children and adolescents at a time when they should be learning at a maximum in school.

That March 2014 Observer article therefore warned that we should be pre-emptive and determine the safeguards needed to protect our children before we decriminalised ganja in Jamaica.

GANJA AFFECTS THE DEVELOPING BRAIN

Now research published in the June 2016 edition of the journal Biological Psychiatry has shown that exposure of the developing foetus during pregnancy to cannabis (ganja) in the bloodstream of the mother causes an increase in thickness of the frontal part of the brain that is noticeable in pre-adolescent children. The imaging of the brain was done through magnetic resonance imaging (MRI). The research was conducted in the Netherlands, where the smoking of cannabis (ganja) is legal, and involved participants who reported smoking during pregnancy and their children ages six to eight years of age.

Researchers at the Department of Child and Adolescent Psychiatry, Erasmus University, Rotterdam, divided the children into three groups: 113 children who were not exposed to cannabis during pregnancy; 96 children whose mothers smoked only tobacco (cigarettes) during pregnancy; and 54 children whose mothers used cannabis during pregnancy. The MRI results showed that, when compared with the non-exposed children, the tobacco-exposed children had smaller global brain volume. When compared to the non-exposed children, those exposed to cannabis during pregnancy had thicker frontal cortices (the outer layer of the frontal brain) and, more specifically, a thicker superior frontal area of the left hemisphere, and a thicker frontal pole of the right hemisphere.

AN ALTERATION IN BRAIN MATURATION

The researchers proposed that the increase in thickness of the prefrontal cortex reflected an alteration in neuro-developmental maturation. The prefrontal cortex is involved in cognitive functions (perception, memory, judgement, and reasoning), and is one of the ‘higher order’ regions of the brain that undergoes maturation later than ‘lower order’ regions, such as those concerned with interpreting body sensations (somato-sensory) and visual functions.

The prefrontal cortex thus supports functions such as rapt attention, higher order motor (muscle) control, the ability to suppress thoughts and responses, and working memory.

The current research, when combined with the existing medical literature about the long-term consequences of prenatal cannabis and tobacco smoking, support the importance of reducing or totally preventing the use of these substances during pregnancy. The research also noted that some smokers use both cannabis and cigarettes. Alarmingly, 74 per cent of smokers continued smoking during pregnancy.

OTHER ASSOCIATIONS WITH GANJA USE

The researchers had previously shown that prenatal cannabis exposure was associated with increased aggression among children and problems in maintaining attention, particularly among girls. Further, as the children became older, the association became more evident. Other research studies have also linked the use of cannabis (ganja) during pregnancy with lower scores on assessments of language, memory, and visual and abstract reasoning in offsprings.

The findings from these studies have, therefore, led to the belief that the use of cannabis during pregnancy may have selective harmful consequences on the developing executive functions within the higher brain.

In some adults, ganja has also been known to cause anxiety, panic, and compulsive habitual use. Ganja-induced psychosis has also been known to occur. We also know that driving under the influence of ganja can cause accidents. Unfortunately, because its use within our culture has been historic, many people are not conversant with the evidence from research about its possible harms. So the decriminalisation of ganja should have been preceded by a widely pervasive public education campaign on the matter.

We are now beginning to reap the consequences of that grave oversight, if not negligence!

Derrick Aarons MD, PhD is a consultant bioethicist/family physician, a specialist in ethical issues in medicine, the life sciences and research, and is the Ethicist at the Caribbean Public Health Agency – CARPHA. (The views expressed here are not written on behalf of CARPHA)