The War Against Marijuana

[boulder]

In Pakistan, cannabis use has reached alarming proportions among young people, particularly in the urban population. In large cities such as Karachi, Lahore and Islamabad, smoking a "joint" for relaxation is considered "fashionable and the in thing." Parents from the upper social classes, if not encouraging its use, do not care if their children smoke hash off and on, during weekends or at parties. About 80 to 90 per cent adolescents and young college students in most of the elite schools have tried hash.

 

Although most young people use cannabis in adolescence without apparent harm, clinical research studies over the last decade clearly indicate that a number of vulnerable adolescents develop a form of schizophrenia by the age of 26. Most of the research studies suggest that the use of cannabis among psychologically vulnerable adolescents should be strongly discouraged by parents, teachers and health practitioners. Policy-makers and law- makers should also concentrate on delaying the onset of cannabis use.

 

The use of cannabis is very prevalent worldwide and the association with depression, conduct problems, excessive drinking and use of other drugs shows a malignant pattern that may lead to negative outcomes. Cannabis was associated with an increased risk of developing schizophrenia in a dose-dependent fashion both for subjects who had used drugs and for subjects who had used only cannabis and no other drugs.

 

In young people, the use of cannabis is known to cause mood disorders. In one study, some 60pc of the participants had used cannabis by the age of 20; seven per cent were daily users at that point. Daily use in young women was associated with an over five-fold increase in the odds of reporting a state of depression and anxiety after adjustment for intercurrent use of other substances. Weekly or more frequent cannabis use in teenagers predicted an approximately two-fold increase in risk for later depression and anxiety.

 

Hence, frequent cannabis use in teenage girls predicts later depression and anxiety, with daily users carrying the highest risk. Given the recent increasing levels of cannabis use, measures to reduce frequent and heavy recreational use seem warranted. Cannabis use in adolescence and risk for adult of major psychiatric illnesses is now well established. The strongest evidence that cannabis use may be a risk factor for later psychosis comes from a Swedish cohort study which found that heavy cannabis use at age 18 increased the risk of later schizophrenia sixfold. This study could not establish whether adolescent cannabis use was a consequence of pre- existing psychotic symptoms rather than a cause. A local study in Karachi, taking into account childhood psychotic symptoms, also shows an association between cannabis use and the onset of schizophrenia.

 

The Dunedin multidisciplinary health and development study (a study of a general population birth cohort of 1,037 individuals born in Dunedin, New Zealand, in 1972-3) has a 96pc follow-up rate at age 26. It obtained information on psychotic symptoms at age 11, and drug use at ages 15 and 18 from self reports and assessed psychiatric symptoms at age 26 with a standardized interview schedule. Data was analyzed from a representative group of 759 (74pc) living study members who had complete data on adult psychiatric outcomes, adolescent use of illicit substances and childhood psychotic symptoms.

 

The sample was divided into three groups based on cannabis use at ages 15 and 18. The 494 controls (65.1pc of the sample) had reported using cannabis "never" or "once or twice" at both ages; cannabis users by age 18 (236; 31.1pc) first reported using cannabis "three times or more" at age 18; and cannabis users by age 15 (29; 3.8pc) had reported using cannabis "three times or more" at age 15 (all of whom continued to use cannabis at age 18).

 

Multiple linear regression analyses showed that cannabis users by age 15 and 18 had more schizophrenia symptoms than controls at age 26. These results remained significant after psychotic symptoms at age 11 were controlled for. The effect was stronger with earlier use.

 

Logistic regression analyses showed that people who used cannabis by age 15 were four times as likely to have a diagnosis of a form of schizophrenia at age 26 than controls. Cannabis use by age 15 did not predict depressive outcomes at age 26. Use of other drugs in adolescence did not predict schizophrenia outcomes over and above the effect of cannabis use.

 

Using cannabis in adolescence increases the likelihood of experiencing symptoms of schizophrenia in adulthood. Local clinical findings agree with those of the Swedish study and add three new pieces of evidence. Firstly, cannabis use is associated with an increased risk of experiencing schizophrenia symptoms, even after psychotic symptoms preceding the onset of cannabis use are controlled for, indicating that cannabis use is not secondary to a pre-existing psychosis. Secondly, early cannabis use (by age 15) confers greater risk for schizophrenia outcomes than later cannabis use (by age 18). The youngest cannabis users may be most at risk because their cannabis use becomes longstanding. Thirdly, risk was specific to cannabis use, as opposed to use of other drugs.

 

To determine whether cannabis use in adolescence predisposes to higher rates of depression and anxiety in young adulthood, in 44 schools in the Australian state of Victoria, samples were taken from 1,601 students aged 14-15 for seven years.

 

Some 60 per cent of participants had used cannabis by the age of 20; seven per cent were daily users at that point. Daily use in young women was associated with an over five-fold increase in the odds of reporting a state of depression and anxiety after adjustment for intercurrent use of other substances (odds ratio 5.6, 95pc confidence interval 2.6 to 12). Weekly or more frequent cannabis use in teenagers predicted an approximately two-fold increase in risk for later depression and anxiety. In contrast, depression and anxiety in teenagers predicted neither later weekly nor daily cannabis use.

 

Drug websites: Targeting teenagers and young adults with health education messages is notoriously tricky. Drug websites aimed specifically at the youth population, specially those developed and maintained by young people themselves, may be the key.

 

Source: Independent (Dhaka, Bangladesh)