Is Cannabis Addictive?

By Ann Stoker, B.A., NDPA.


Cannabis information for parliamentary briefings, leaflets and general articles needs to be clearly stated and simple – but with scientific references to source materials. The general public, and young people in particular, have been, and are being, given misinformation, insufficient information or totally incorrect information in many of the leaflets issued by other agencies. Most of these leaflets repeat messages from large organisations such as DrugsScope, (an organisation which was formed from the merging of two other groups ISDD and SCODA) or Connexions. ISDD had been disseminating out of date information for years yet an offer of help with updating the ISDD information on cannabis by a biology teacher specialising in the subject was refused.


Given the known harmfulness of cannabis it would be unethical to try to replicate some of the small scale studies which showed significant harm from the use of the substance, The claim that millions worldwide use cannabis is no reason to ignore the harm which the small studies identify, and there are other quite large scale studies showing different elements of possible harm. In the USA there were 77,000 admissions to hospital emergency rooms in 1998 due to the use of cannabis. In the last year or two more and more psychiatrists and doctors have been publicising the fact that thousands of people are suffering from mental illness due to their use of cannabis. In the National Health Service in Britain there is a ‘yellow card scheme’ where GPs who come across even a few examples of contra-indications to prescribed drugs send in the card to flag up ‘caution’. These cautions are taken very seriously since the widespread prescribing of certain drugs could result in another situation Like thalidomide if not identified early on. This scheme could be adopted to note any physical or mental illness which doctors believe is due to their patient’s use of cannabis. We should take notice of any studies showing harm in so many areas from the use of cannabis. The fact that thousands may use and have no apparent adverse effects is of no consequence – many pharmaceutical drugs are withdrawn from general use when they harm a few – even though they may help many others. Professor Gabriel Nahas writes very eloquently on this very point:

The protagonists of the free availability of cannabis who are convinced that this drug does not constitute a serious health hazard will claim that those who wish to ban cannabis must produce convincing reasons before we restrict the individual’s right to choose (Schofield. 1971) – This view is a transposition of a legal concept regarding man’s innocence until proven guilty into the field of medicine, where a different viewpoint prevails in respect to drug usage. indeed, physicians have to take a guarded view of all drugs. which are considered guilty until proven innocent. The state which has the mandate to protect the health of the people, must hold a view similar to that of the physician.
Professor G. Nahas ‘Marijuana – Deceptive Weed’ 1975 Published by Raven Press

It is clear therefore that saying ‘millions use cannabis’ or ‘ I use and it never did me any harm’ is the same as saying that millions drink alcohol and they are not all alcoholics. True. But many are – and the younger they are when they begin to use alcohol the more likely they are to become problem drinkers. Cannabis is no different and more and more research is being published which shows that early onset use of cannabis and other illegal drugs leads to more problematic and chaotic drug use in later life.


The often quoted figures that millions’ use cannabis world-wide or’ 2 -6 million have used cannabis in the UK – are themselves very misleading. Several years go the figure of 2 million users in the UK was bandied about – now one reads ‘Up to 6 million users’. Firstly, where is the hard evidence? The activity is illegal and therefore difficult to portray accurately. Were they users in their youth and are they now non-users ? Have these users tried the drug once, twice or many times ? Did they use daily, weekly, monthly, three times a year or once every five years? Did they smoke ditchweed, grass, ganja, resin, sinsemilla, skunk or chaw? These questions are important because the very real harms from the use of cannabis will vary from person to person and are dependent upon the age of onset of use, the length of time used, the frequency of use, the type and purity of the drug used, the strength of the drug used. Thus it is not possible to compare a 50 year old intelligent male who has occasionally smoked an 0.5% THC joint at parties – from the age of 18 – perhaps a total of 100 low potency joints in his life, to an unemployed and alienated young man of 18 who started smoking 0.5% THC joints at 13 years of age and was a daily smoker of skunk (15 – 27% THC) by 15 – which could be well over 700 joints in 2 years. The risks to their health, their education, their employment prospects, their family and social life and their relationships with the opposite sex will be very different.


There is plenty of research that shows cannabis to be an addictive substance. The following authors have all written affirmatively on the subject of addiction.

One of the single most important reasons why there has been an upsurge in the use of illegal drugs by Western youth is the mistaken belief that marijuana is a ‘soft’ drug. not physically addictive, and mood-altering rather than mind altering. Studies of the characteristics of drugs and patterns of their use and the observations of patients, doctors, teachers and ex-drug users have made it clear how misleading these assumptions have been.
Elaine Walters Marijuana – An Australian Crisis’ 1993

Cannabis is readily available on the streets. Were it to be legalised the addiction rate would inevitably he greater. The following quotation concerned narcotics but the point is made that greater availability of drugs leads to greater addiction.
‘The addiction rate to narcotics among the medical profession is estimated to be 30-50 times greater than that of the general population. These statistics suggest that easy availability and the inherent addictive properties of narcotics are important factors…….
Nils Bejerot, ‘Addiction. An Artificially Induced Drive’ published by Charles Thomas. USA

Like all addictive substances, cannabis is not easy to give up. Some believe that it is more difficult to stop all use of cannabis than it is to stop the use of most other drugs.
A marked and rapid tolerance to most of the physiological and neuropsvchological effects of THC occurs. Withdrawal symptoms occur after cessation of heavy daily cannabis administration. As is the case for other drug dependencies, there is no pharmacological cure for cannabis dependency. Therefore, as for treatment of other dependencies, that of cannabis should employ methods that aim at abstinence from the drug so as to foster a drug-free life. Long-term cannabis smokers are difficult to treat because of their denial of the progressive and subtle negative effects of their dependency.
Gabriel G. Nahas, MD. Ph.D. D.Sc. ‘A Manual on Drug Dependence’ 1992
published by Essential Medical Information Systems. Durant. USA
In a study including people who used both cocaine and marijuana, many stated that giving up the use of marijuana was in some ways more difficult than giving up cocaine.
Strategies for breaking marijuana dependence. Zweben & O 1992 (2):165-71
Published in Journal Psychoactive Drugs
Clinically there is no doubt that psychological dependence on marijuana can and does occur. It is the drug of choice of many of the adolescents in our clinic. … Symptoms of psychological dependence parallel those seen in classic adult-onset alcoholism, and, in fact, such a model seems to serve very well for marijuana dependence. Symptoms such as increasing use to the point of tolerance, solitary use, surreptitious use, symptomatic use, blackouts, personality change when intoxicated, inability to control the amount used, preoccupation with use, inappropriate use, and use despite adverse consequences are seen regularly in our adolescent patients… irritability, anorexia, insomnia, and intensive drug seeking behaviour upon cessation of marijuana use (with) relief of these by return to marijuana use.
…a major clinical issue (is that) many children are referred to paediatricians, child psychiatrists and other health care workers for problematic behaviours and the child is not recognised as an extensive marijuana user.., because health care personnel often do not inquire about such drug use, or if they do inquire the child will minimize the extent of use.. there is extensive enabling behaviour , of both an active and passive nature, among school officials, parents and some professionals who deal with children. There appears to be a need for research and education regarding this behaviour if we are to increase our effectiveness in identifying those individuals whose drug use is problematic and in intervening as early as possible.

Marijuana and Youth – Clinical Observations on Motivation and Learning. pages 98-99 Robert Niven M.D.
Published by the National Institute on Drug Abuse. 1982
The prevalence and severity of psychiatric problems and addiction associated with cannabis, has resulted in ‘marijuana-related-dysfunctioning’ being one of the most frequent admission diagnoses in drug treatment facilities.
TheCannabis Connection by Elaine Walters Australia. 1989
Surveys indicate that the percentages of excessive consumers of illegal dependence producing drugs are related to the respective addictive properties of the drugs. Experts have concluded that marijuana addiction frequency, though not as high as cocaine or heroin, is far higher than alcohol. Still when someone has become dependent on marijuana the addiction is as severe and difficult to treat.
In 1968 the official classification of psychiatric disorders did away with the term addiction, replacing it with dependence… The result of a sudden termination in use of the drug of addiction, the withdrawal reaction, is well known in the cases of heroin and alcohol. That it occurs with the marijuana discontinuation, to a different degree, is not generallv appreciated.
Bitter Grass – The Cruel Truth About Marijuana by Roy Hanu Hart M.D. Published by Psychoneurologia Press
in Cooperation with the American Academy of Psychiatry &Neurology (AAPN). Kansas.

The pharmacological classification of dependence-producing drugs is as follows:

Toxicity to brain cells (neuropsychological toxicity) with impairment of mental functions and changed perception of reality (‘spaced out’)
A primary pleasure reward from chemical effects on the Limbic Area of the brain, (‘the pleasure centre’).
Craving, compulsion and repetitive self-administration.
Tolerance with daily use; a progressively greater dose needed to get a high.
Mental and/or physical damage from acute or chronic use.

There is also a summary of dependence in decreasing order of severity:

Major psychostimulants – cocaine, amphetamines.
Psychodepressants – Alcohol if greater than 30 mls. per day.
barbiturates. benzodiazepines.
Cannabis (is a psychodepressant but also a stimulant and a hallucinogenic – depending on type used, eg grass, resin or chaw). Hallucinogens – LSD, PCP, Magic mushrooms etc.
Volatile solvents (e.g. aerosols, glue, acetone etc.)
Minor psychostimulants (caffeine etc.)

Source: Marijuana. Elaine Walters Assoc.Printers. AustraliaISBN 0 646 15066 9

Using the above definitions, and just a few extracts from scientific and medical writings, it is clear that cannabis is both physically and psychologically addictive – as any worker in a drug rehabilitation centre could confirm. Relativists say it’s not a problem because it’s only psychologically addictive – in fact psychological addiction is a bigger problem than physical. It is immaterial as to whether cannabis is physically or psychologically addictive (some would say both); there is research to show that cannabis is one of the most difficult drugs to give up and relapse following de-tox. is very common. That is addiction.


Provided the assertions can be backed up by references to source materials, it is essential that cannabis details are truthful – even if they are considered by some to be ‘hard-hitting’. It has been suggested that NDPA should ‘play down’ the harmfulness of cannabis, and not to become involved in the ‘debates’ over legalisation issues. This would be a very short-sighted strategy – the legalisers hide behind pseudo-scientific groups and big money organisations (Drug Policy Alliance, Lindesmith Institute etc.) and will themselves be citing ‘technical’ papers written by their own members (Nadelmann, Zimmer, John Morgan etc. etc.) – who clearly have an axe to grind. Without pointing up the connections between the legalisation movement and some of the misinformation being published (and posted on the Internet), young people may well accept at face value the ‘facts’ they are given by such people.

It needs to be made clear that when reading any research about drugs in general and cannabis in particular, the credentials and affiliations of the authors should be checked carefully. Even ‘evaluations’ can be biased. Scientists or academics who are members of legalisation bodies do produce ‘research’ which puts an attractive and acquiescent spin on drug use. Many of these have publicly admitted that they themselves use illegal drugs. Scientists and medics who publicise studies which show the opposite may belong to anti-legalisation groups – and some have joined these groups because they have first hand experience in their professional capacities of the problems caused by drug use. In between these two dichotomous groups are a large body of professionals with no affiliations to anti or pro-legalisation groups, and who, year after year. add to the body of knowledge about drugs, especially cannabis. The University of Mississippi has over 15,000 research papers about cannabis ‘and none of them give it a clean bill of health.

The following are some quotations from the proceedings of the Second International Symposium ‘Cannabis. Physiopathology, Epidemiology, Detection’, organized by the National Academy of Medicine in Paris in April 1992. This congress consisted of 53 renowned scientists from all over the world who presented papers on cannabis.

‘At a time when strong voices are advocating the relegalisation of illicit drugs, and public health is threatened by the progression of illicit drug consumption, the City of Paris is proud to support outstanding scientific studies which should help to promote prevention programmes for your youth. ….(scientists) are now seeking methods to curtail the use and trivialisation of substances which pollute the internal milieu of man’s brain and physical health and especially that of future generations. Such is our hope and our goal’.
Jacques Chirac. Mayor of Paris. Former Prime Minister of France.
‘And today, all the clinical symptomatology of cannabis intoxication described so accurately by Moreau, (in 1845), and which has been confirmed by many other psychopharmacologists, is being reinvestigated and correlated with biochemical and neurophysiological markers of the brain. Such studies will be discussed in this colloquium which should be another landmark in our understanding of the human brain.’
Henri Baruk. Prof. Honoraire de La Faculte de Medecin

The general conclusions of this international conference were as follows:

1. The toxicity of cannabis is today well established, experimentally and clinically. This drug adversely effects the central nervous system, the lung, immunity and reproductive function.
2. Epidemiological studies have reported that the use of ‘hard drugs’ rarely occurs among subjects who have never consumed cannabis.

3. Consequently, the participants to this colloquium rebut the distinction made between soft and hard drugs.

4. The trivialisation (decriminalization) of cannabis use, where it has occurred, has resulted in a considerable increase of its consumption and of its subsequent damaging effects.

5. It is important to foster a campaign of information and prevention bearing both on the legal aspects and the health consequences of cannabis consumption.

Professor Henri Balon. President. French National Academy of Medicine. April 1992.

The continued increase in the use of illegal drugs, by young people in particular, is a cause for great concern. As Elaine Walters (Australia) wrote so cogently in 1993:
Experience shows that one cannot be in favour of legalisation, and hope to discourage drug use by youth. In the USA during the period in which eleven states decriminalised marijuana half of high school seniors were using, or had experimented with marijuana and 11% became intoxicated daily. ….Drug legalisation will result in more people experimenting with drugs, more experimenters becoming regular users and more regular users becoming addicts.
‘Marijuana – An Australian Crisis’ Elaine Walters 1993.

Many young people receive out of date information from leaflets widely distributed by schools, health promotion units, youth clubs, young peoples’ counselling services etc. They read in newspapers, or watch on television, pseudo debates about ‘de-criminalisation of cannabis’, they are told that they should make their own ‘informed choices’ about use or non-use and that they should ensure that they use ‘responsibly’.

‘The dramatic increase in illegal drug use among adolescents and young adults indicates that drug education programmes in schools need to be reviewed …relevant, accurate and up-to-date information is an important part of the whole approach. No choices should be given to young people about illegal drugs, and their use cannot be regarded as a civil right or privilege. ‘Just Say No’ is a clear and concise message. ….Young people should be taught how to evaluate advertisements, and how to recognise promotion of drug use in music videos, records and other commercialised forms of entertainment. Drug use and under-age drinking among adolescents should not be regarded as ‘normal’. Neither should it be regarded as a psychological problem. It is a behavioural problem which requires correction, intervention and common sense from parents, teachers and members of the community.

We must give the public, and especially young people, information about cannabis which is clear, up-to-date and unequivocal. NDPA acknowledges this need and will continue to provide such information.

Back to top of page - Back to Papers

Powered by WordPress