Effects of use
The effects of using cannabis, and the duration of those effects, vary greatly from person to person and according to the strength used and the expectations and mental state of the user. An inexperienced or irregular user can expect the effects of one cannabis cigarette of medium strength to produce effects that will last for between two and four hours, with the effects tapering off after that.
Most users will experience a feeling of bodily warmth, which is a purely physical reaction to the drug. The small blood vessels close to the surface of the skin dilate and suffuse with blood. This gives the skin a flushed appearance and makes it warm to the touch. It also leads to the characteristic cannabis user’s bloodshot eyes known as ‘cannabis red eye’.
Users often report a feeling of relaxation, happiness and congeniality, with them taking a great deal of pleasure from the company of other people around them. If these other people are also using cannabis, then there is the potential for very pleasurable experiences. Many cannabis users make use of the drug in order to give themselves confidence in social situations and find that it helps them to mix with others and to make friends. Cannabis users often become very talkative and report that the drug has opened their minds and given them such insights that they are able to have the most wonderful conversations with other cannabis users about all sorts of subjects, including the big questions of life, love, religion and death. The truth of this is very different: we have listened many times to these conversations as sober observers and have found them to be utter drivel and to make no sense at all. A common feature of these conversations is the ‘unfinished sentence effect’, otherwise known as the ‘ums’, in which the user will forget the subject of their conversation halfway through and the sentence will tail off in an extended ‘um …’.
Some users claim that cannabis in low doses temporarily increases their powers of concentration, and many young people use it as an aid to studying and revision. They feel that the drug enables them to study for longer periods without fatigue. Most users will lose their inhibitions and do things that theywould never dream of doing when sober. In some users, cannabis raises sexual awareness; this, together with the loss of inhibitions, may lead them to have unprotected sex, sometimes resulting in unplanned pregnancy or the transmission of various diseases.
At low or infrequent doses, the adverse effects of cannabis are fairly mild; many users report few if any adverse effects. Some users suffer from dryness of the mouth and throat if the cannabis has been smoked, and some will suffer bouts of nausea and dizziness. An increase in appetite is experienced by most users. Many users experience ‘the munchies’, during which they consume large quantities of food, often stripping the refrigerator on their return home of anything edible, even things that they would not normally eat.
At comparatively low levels of use, many users suffer from short-term memory loss, with no retention of any clear memory of events occurring during and immediately following their use of the drug. This makes a nonsense of the use of the drug as an aid to studying. Such users maywell have the powers of concentration that learning requires, but the drug prevents them retaining much of what they have been studying.We have had a great deal of contact with students in ourwork and have often been told by them of their realisation, sometimes too late, that their use of cannabis while studying had a deleterious effect on their grades.
Even at these low levels, cannabis has a powerful effect on the judgement and information-processing skills required to perform complex tasks such as driving a car or even riding a bike. In 2000, the UK Department for Transport published a research report into the effects of cannabis on driving.1 They concluded that cannabis impairs driving in many of the same ways as alcohol does but that many cannabis users adopt a more cautious driving style than those affected by alcohol. Thus, the adverse effects of cannabis use can, to a certain extent, be mediated by a change in driving style.
Many cannabis users who make regular use of the drug report that time appears to run at a different rate than normal. This ‘cannabis time’ runs much more slowly, with minutes feeling like hours. Some users report that they feel that they are walking in slow motion when under the influence of the drug. As the dose increases, many users begin to suffer the onset of many of the more unpleasant side effects of cannabis. THC is a moderately powerful hallucinogenic substance, and users will begin to experience an altering of their perception of the world around them. Their hearing may be enhanced and low-level sounds may be exaggerated until they reach unpleasant or even frightening proportions. Light levels and colours may change, causing confusion, disorientation and nausea. The initially pleasant feeling of relaxation and happiness may be replaced by anxiety, panic and eventually paranoia.
Many users report that they feel trapped insidewhat they are still able to recognise is a false reality created by the drug and feel that it is never going to end.
Although rare, full-scale hallucinations are possible with high doses of cannabis. These ‘trips’, unlike those induced by some other hallucinogenic drugs, are almost always unpleasant and can be positively terrifying.
Trying to make sense of all of the available information about the long-term effects of regular cannabis use is very difficult. Our current state of knowledge can be likened to the position that society was in some years ago with our knowledge of the health problems associated with the smoking of tobacco. Research had revealed some very serious problems, such as lung cancer and heart disease, but as time went on further research was to reveal much more. Medical research of a similar nature into cannabis use is still in the early stages, but it is beginning to reveal some worrying evidence.
Perhaps the most concerning effect of regular cannabis use by young people is that their use of it as a way of dealing with the ups and downs and the stresses and strains of modern life means that they fail to learn the necessary coping skills to deal with such problems in the real world. Such coping skills can be learnt properly only when a person is young – trying to learn them effectively during adulthood is difficult if not impossible. If a young person fails to learn those skills, they will have great difficulty in dealing with adult life, and many will find that they can cope with the pressures of life only by using drugs – and often potentially much more dangerous drugs than cannabis.
Many regular users of cannabis demonstrate a loss of basic motivation, sometimes called amotivational syndrome. It seems clear to us from having dealt with many such young people that it is not possible to place the blame for this solely on the use of cannabis. Many of these unmotivated young people were performing badly at school and demonstrating similar forms of unmotivated behaviour before they were using cannabis, and, at worst, the cannabis simply exacerbated a pre-existing condition. It is not uncommon for such young people to drop out of school or college, to give up work and to opt out of life in general. Most will have no goals – and see no point in having any. Their lives may be characterised by drift and increasingly will become built around their drug use.
Cannabis is certainly cancer-causing. The smoke produced by burning it contains about 50 per cent more known carcinogens than the same volume of cigarette- tobacco smoke and deposits around four times as much tar in the lungs and bronchial passages of the smoker. This is not as straightforward as it seems at first glance. Most people who smoke only tobacco consume much greater amounts of their chosen drug than do people whose choice is cannabis. Having said that, it is not so unusual now as it once was to find people who use amounts of cannabis that
approach the amounts of tobacco consumed by many cigarette-smokers. There are also important differences in the way users smoke cannabis. Most users of cannabis will inhale much more deeply than most tobacco-smokers do and will, in order to extract the maximum effect from it, retain the cannabis smoke in their lungs for much longer. This means that the smoke will be in contact with the membranes of the throat and lungs for a greater period of time than is usual with cigarette-smoking.
The picture is confused further by the facts that most cannabis is smoked mixed with tobacco and that most cannabis-smokers also smoke tobacco cigarettes.What is clear is that there are growing numbers of documented cases of throat, mouth and lung cancers that appear to be connected directly to the smoking of cannabis.
A 2005 review of cannabis-related health risks by the drugs information charity DrugScope drew attention to a number of cases of cancers of the digestive tract found in young adults with a history of heavy cannabis use. These forms of cancer are not common in people under the age of 60 and further highlight the carcinogenic potential of cannabis.
There can be serious problems for the fetus growing in the womb of a woman who uses cannabis. Cannabis crosses the placental barrier and enters the bloodstream of the unborn infant, who will be affected in the same way as the mother, but to a much greater extent. Put bluntly, when a pregnant woman is stoned, so is her child. The developing fetus is very delicate and susceptible to damage caused by the actions of drugs taken by the mother. Firmevidence on this issue is difficult to come by and can be contradictory. Female users of cannabis during pregnancy will, in our experience, often use a range of other substances, including tobacco and alcohol.
Such multi-drug use can make it difficult to separate the causal agents of any subsequent health problems in the baby.What does seem clear is that use of cannabis on any regular basis during pregnancy can lead to reduced birth weight and a range of problems during the child’s early years, including attention, memory and cognitive functioning deficits.
Cannabis has an effect on the level of the hormone testosterone in males. This is the hormone that provides masculine characteristics. As soon as a male begins to use cannabis, his testosterone level reduces. If he stops using the drug, the level will return quickly to normal. The real problems occur in males, particularly those with a predisposition to sperm-production problems, who continue to use cannabis on a regular basis and over an extended period.
Research indicates that in some males, the reduction in testosterone level becomes permanent and the level becomes so low that problems are then experienced in achieving or maintaining an erection and performing sexual intercourse. It would seem to us that these things are of some importance to most young males and something they ought to consider. One of the most worrying aspects of chronic use of cannabis by young people is the link between such use and its potential adverse effects on mental health. In our conversations with many hundreds of young cannabis users over the years, it has become clear to us that this aspect of the health issues surrounding cannabis is the one that concerns them most. Cannabis in high doses can precipitate an acute psychosis in some users. This manifests itself in anxiety, confusion, agitation, hallucinations and delusions.What is also becoming apparent is a link between cannabis use and schizophrenia. Although it remains unclear as to whether cannabis use alone can cause schizophrenia in otherwise mentally healthy young people, the drug does seem to precipitate schizophrenia in people who may already be vulnerable to the illness. The conclusion seems to be that any young person with a family history of schizophrenia would be extremely unwise to make cannabis use a part of their lifestyle.
This research is ongoing, and it seems likely thatmuch more information will be revealed yet. What can be said with certainty at this stage is that cannabis is not a harmless herb, as some would have young people believe, but a powerful drug that no-one should underestimate.