Position Paper

ARTICLE 2

Abstract: 

A high incidence of positive cases for cannabinoids, in analyses for doping control in  sports , has been observed since the International Olympic Committee (IOC) included them in the 1989 list of prohibited drugs under the title of classes of prohibited substances in certain circumstances. Where the rules of sports federations so provide, tests are conducted for  marijuana , hashish or any other cannabis product exposure by means of  urinalysis  of 11-nor-delta-9- tetrahydrocannabinol -9-carboxylic acid (carboxy-THC) the main metabolite of delta-9-tetrahydrocannabinol (THC). Concentrations >15 ng/mL (cut-off value) in confirmatory analytical procedures are considered doping. Cannabis is an illicit drug in several countries and has received much attention in the media for its potential therapeutic uses and the efforts to legalise its use.

Studies have demonstrated that the use of cannabinoids can reduce anxiety, but it does not have ergogenic potential in sports activities. An increase in heart rate and blood pressure, decline of cardiac output and reduced psychomotor activity are some of the pharmacological effects of THC that will determine a decrease in athletic performance. An ergolytic activity of cannabis products has been observed in  athletes  of several different sport categories. In Brazil, analyses for doping control in sports, performed in our laboratories, have detected positive cases for carboxy-THC in  urine  samples of soccer, volleyball,  cycling  and other athletes.

It is our intention to discuss in this article some points that may discourage individuals from using cannabis products during sports activities, even in the so-called permitted circumstances defined by the IOC and some sports federations.

The use of substances to increase athletic performance has occurred throughout the world since the appearance of sports competition in ancient Greece, the birth of the modern Olympic  Games . [1] From the  1960s  on, together with the development of pharmacology, the use of doping has become so frequent in sports competitions that in 1967 the International Olympic Committee (IOC) was forced to make up, for the first time, a list of substances subjected to restriction during sports activities. As a consequence, tests were conducted for doping control among athletes of the 1968 Olympic Games held in Mexico City. [2]

With the development of urinalyses, the detection of a large number of drugs was becoming more and more possible, with some of them frankly recognised as doping. Thus, lists of prohibited drugs proposed by the IOC were successively updated permitting the inclusion of new ergogenic-claimed compounds such as: anabolic  steroids  in 1976,  diuretics  and [beta]-adrenergic blocking agents in 1985,  peptide hormones  in 1989, and non-steroidal anabolic agents ([[beta].sub.2]-receptor agonists), like clenbuterol, in 1993. Cannabis products were also put on IOC lists under certain restrictions for sports purposes in 1989. [3]

The products of Cannabis sativa, such as marijuana, hashish, hash oil, sensemilla and others, obtained from different parts of the plant, are considered to be the most popular illicit drugs throughout the world. Historically, these products were already used in the Chinese Empire in 2700BC in the treatment of malaria and rheumatism. [1,4]

More than 400 different compounds, distributed by 18 chemical groups, were detected in different species of cannabis plants. The most important group is the cannabinoids, in which the substance delta-9-tetrahydrocannabinol (THC) is the most significant compound, due to its psychoactive properties. [5,6] THC was scientifically proven to be effective against some AIDS symptoms and adverse effects of cancer chemotherapy. A THC synthetic product, named dronabinol, has recently been approved in many countries to be prescribed in a capsulated form named Marinol. [R] (1) First brought onto the market in 1985, Marinol [R] has been used to treat anorexia and  weight loss  associated with AIDS, and nausea and vomiting associated with cancer therapy, with very good results. [7]

According to the US legislation, (United States Federal Status) [6] the term marijuanaencompasses all parts, extracts and products of the cannabis plant, including the oil. However, the name marijuana is normally associated with a mixture of ground-dried leaves, inflorescence and other parts of the plant conveniently prepared to be smoked, as the illicit drug cannabis is commonly consumed in the form of marijuana or hashish in cigarettes or even in small pipes. [6]

The rate of absorption of the active component (THC) by the lungs is very high; consequently, immediate effects can occur depending on the dynamic of the smoking act: the duration and time interval of each inhalation, as well as the quantity of smoke inhaled. [4,5] For one cigarette smoked, maximal blood concentrations are normally obtained after 3-8 minutes, the onset of action on the CNS is observed in approximately 20 minutes and peak effect in 2-4 hours. Duration of action for psychoactive effects is 4-6 hours. [4,6]

THC is biotransformed in the liver to 11-OH-THC and carboxy-THC, the main metabolite found in urine. [8]

Cannabinoids present a high lipid/water partition coefficient. Thus, they may be stored in body fat and slowly excreted with urine. They inhibit the liberation of acetylcholine in the hippocampus, which is the region of the CNS responsible for cognitive activities, such as learning and memory. Noradrenaline liberation is also inhibited in the regions of the cerebral cortex and cerebellum, which are responsible for alertness and motor co-ordination, respectively. [9,10]

Recently, cannabinoid receptors, both centrally and peripherally, were characterised. Centrally, they are present in cerebral areas such as the cerebellum, hippocampus, basal ganglia and cortex. Furthermore, an endogenous ligand for the cannabinoid receptor, named anandamide, was also identified. It is a fatty-acid-derived compound with pharmacological properties similar to delta-9-THC. The production of complex behavioural events by cannabinoids is probably mediated by specific cannabinoid receptors and interactions with neurochemical systems. [9,11]

Anandamide binds to CB1 and CB2 receptors in the CNS, and to cells of the immune system, modulating physiological, cognitive, motor and humoral responses. [9,10]

1. Detection of Cannabinoids in Urine Samples

Urine is the mandatory biological sample in doping control, due to easy collecting and its noninvasive nature. The bicompartmental kinetics of cannabinoids explains the fact that in urine samples of occasional cannabis users, cannabinoid metabolites can be detected up to 5 days after the exposure. For chronic users, however, carboxy-THC can be detected as long as 30 days after the last exposure, whenever sensitive analytical techniques are used. [12-15]

According to international guidelines accepted by the US National Institute of  Drug Abuse , the detection of cannabinoids in urine samples must be performed in two steps: [16]

* An  immunoassay  technique for the detection of cannabinoids, with a cut-off limit of 50 [micro]g/L, will be considered as a screening test.

* A confirmatory test, with a cut-off limit of 15 [micro]g/ L of the carboxy-THC, must be performed using gas  chromatography  coupled with mass spectrometry (GC/MS).

2. Cannabis and Sports Competitions

The study of the prevalence of the use of drugs in sports may show the social reality of a country, as well as its sports activity status. Statistics derived from results obtained in laboratories accredited by the IOC show the frequent use of drugs, even in international competitions, which aggregate athletes worldwide.

As far as cannabis is concerned, its use is becoming widespread in society and the effects of this on sports activities are becoming evident. [2] As a consequence, results of doping control analyses have demonstrated marked positive results for cannabinoids. [17] Thus, from 1989 onwards, cannabis has been included in the lists of drugs subject to certain restrictions edited by the IOC, with or without sanctions for the athletes who are caught using them. However, prohibition will depend on the particular rules of each sports federation that is involved in doping control during their regional and international activities. Recently, doping control regulations for Federation Internationale de Football Association (FIFA) competitions, and out-of-competition, have changed the category of cannabinoids in the list of prohibited substances. It is now banned, its use subject to sanctions and this is followed by all soccer federations worldwide.

Cannabis is different from other drugs used in doping; it is not considered ergogenic as it does not interfere positively with the athletic performance. However, due to the increasing cardiac frequency, psychoactive and motor alterations that cannabis produces, it is considered an ergolytic drug instead. [18]

According to the IOC, urine samples are considered positive for cannabis exposure if the concentration of carboxy-THC is greater than 15 [micro]g/L, when detected by the GC/MS analytical technique. [3] This arbitrary threshold value corresponds to the concentration from which the positivity of a sample is determined. [19] It also distinguishes active users (smokers) from passive ones (those who are exposed to the smoke in the environment).

Laboratories accredited by the IOC all over the world have also presented data showing that the number of positive results for cannabinoids increased dramatically between 1994-1996. [2] Events surrounding disqualification following positive tests for cannabinoids have been reported in the written media.

In February 1998, at the Winter Olympic Games at Nagano, Japan, Ross Rebagliati tested positive for cannabinoids, was suspended and subsequently reinstated due to a formal agreement between the International Ski Federation and the IOC. [2] More recently in August 2002, the Czech driver Tomas Enge tested positive for cannabis after a Formula 3000 race in Hungary. Enge was conditionally suspended by the governing International Automobile Federation for 12 months, but he can continue driving.

From 1998, some sports federations in Brazil (volleyball, cycling and especially soccer) have included cannabis products in their lists of prohibited compounds subject to sanctions. However, the frequency of tests for cannabinoids in doping control by some sports federations is not high. Sometimes, even in important championships, this kind of analysis is omitted without any explanation by the sports authorities. Table I shows the positive results obtained in our laboratories for carboxy-THC present in urine samples from athletes of different sports activities analysed using a GC/MS technique.

3. Cannabis Abuse in Athletics

Cannabis abuse in athletics is different from other ordinary doping compounds as it reflects, not a search for an enhancement of performance, but a social reality instead. Many countries have reported an increase in cannabis consumption by society in general, suggesting an increase in overall production. The more cannabis is available to ordinary people the more its use can be detected, not only in elite athletes but also in college teams and noncompetitive individuals.

When athletes use anabolic compounds, stimulants or any other ergogenic compounds they are trying to overcome their physiological capacity to reach goals never reached before. Due to its ergolytic action, the use of cannabis as doping will not help to gain a competitive edge by any means. Cannabis makes the heart work harder and limits sports performance. It increases heart rate and decreases cardiac stroke volume. Cannabis reduced the peak performance of ten healthy male cyclists and in another study of 161 athletes who were given THC (215 mg/kg orally), a general decrement in standing steadiness, simple and complex reaction times, and psychomotor skills was observed. [18] Drugs, such as cannabis products, can be very serious in dangerous sports that rely on clear minds, quick reactions and split-second timing.

It can be inferred from the mechanism of brain reward that cannabis will only be efficient in permitting the athlete to escape from social pressures and the relief of anxiety and stress. Some athletes declare peer pressure as a predominant reason for using cannabis products.

Different authors justify the moderate use of cannabis products before sports activities to decrease anxiety, since feeling relaxed is believed to be beneficial in some sports. However, due to its self administration via the pulmonary route, the quantity of delta-9-THC inhaled will vary from one cigarette to another, making it difficult to know if the main effect will be anxiolytic or anxiogenic. [9]

On the other hand, it is necessary to bear in mind that delta-9-THC-derived drugs are commonly used oral medications for patients with HIV and AIDS, that they present such CNS adverse effects as somnolence, dizziness, euphoria, and paranoid reactions. Anxiety, asthenia, facial flushing, palpitations and tachycardia may also occur. When used in higher doses, amnesia, ataxia and hallucinations have been reported. These effects are absolutely incompatible with athletic activities.

Drugs of abuse, including cannabis, when used with a certain frequency are habit forming and mild to severe withdrawal symptoms have occasionally been reported. Dependence is characterised by behavioural alterations that will unfairly influence the emotional and intellectual activities of the athlete.

The ethical aim, to protect athletes from the psychoactive effects of delta-9-THC and reaffirm principles for a better quality of life, has led the IOC to propose sanctions against the use of all products of cannabis.

4. Conclusions

A variety of prohibited drugs present in the IOC list are used by athletes due to their effects on their performance. However, cannabis is only prohibited under certain circumstances, according to the sports federation rules when applied. Cannabis products are illegal in many countries and are prevalent for social use. The intent to use them to enhance performance in sports activities will fail. Consequently, there are no circumstances in which they may be useful. If cannabis was put in the prohibited class of substances in a updated IOC list, it would always be possible to develop programmes to rescue users and show them the social consequences of the hazards caused by the drug. Such attitudes would avoid the disregard of international principles of honesty, equality and worthiness of life that are present in different sports activities, whether official or not.