Marijuana use is associated with numerous detrimental health effects, including frequent respiratory infections, impaired memory and learning, increased heart rate, anxiety, and panic attacks.
Effects on the Brain
Marijuana's effects begin as soon as the drug enters the brain and can last from 1 to 3 hours. As THC enters the brain, it causes the user to feel high by stimulating brain cells to release the chemical dopamine. When the euphoria passes, the user may feel sleepy or depressed and may also get feelings of panic, anxiety, or distrust.
Marijuana affects a person's ability to shift attention from one thing to another and causes damage to short-term memory because of how THC alters the way information is processed by the hippocampus. THC disrupts coordination and balance by binding to parts of the brain that regulate balance, posture, coordination of movement, and reaction time.
Because marijuana contains irritants and carcinogens, it can promote cancer of the lungs and other parts of the respiratory tract. A study comparing 173 cancer patients and 176 healthy individuals produced strong evidence that smoking marijuana increased the likelihood of developing cancer of the head or neck.
The more marijuana that was smoked, the greater the increase in likelihood. Marijuana also produces high levels of an enzyme that converts some hydrocarbons into their carcinogenic form. These levels may accelerate the changes that ultimately produce malignant cells. Additionally, marijuana users typically inhale more deeply and hold their breath longer than tobacco smokers, increasing the lungs' exposure to carcinogenic smoke.
Users who smoke marijuana regularly may experience the same respiratory problems as tobacco smokers, including daily cough and phlegm, symptoms of chronic bronchitis, and frequent chest colds. Continued marijuana use can result in abnormal functioning of lung tissue injured or destroyed by marijuana smoke.
Within a few minutes after smoking marijuana, the user's heart begins to beat more rapidly and may increase by 20 to 50 beats per minute, or even double. Results of a study released in 2001 indicate that a person's risk of heart attack within the first hour of smoking marijuana is four times the usual risk.
CANNABIS CAN ALSO TRIGGER SERIOUS MENTAL HEALTH PROBLEMS!
Short-term > Anxiety or paranoia. > Memory and concentration problems. > Increased risk of accidents ? especially if you drink alcohol as well. Don’t drive or operate machinery at work when you are stoned. > Bizarre thoughts, extreme paranoia or hallucinations. If you or your family have any history of mental illness you are more at risk of experiencing serious problems. Talk to your GP about any psychological and mental health issues. > Problems with your employer or the authorities over using an illegal drug. > Frequent cannabis use during pregnancy may help cause premature birth. Babies may also temporarily suffer tremor and distress.
Long-term > Increased risk of throat or lung diseases ? such as bronchitis and lung, throat or mouth cancers ? especially if you also smoke tobacco. > Dependence ? it makes things worse if you can’t do without it. > Financial problems ? spending more, earning less. > Social isolation ? long-term smokers often say they don’t mix with other people as much as they used to. > Less motivation ? people dependent on cannabis struggle to achieve their goals and say they regret wasted time and opportunities. > Less concentration, less ability to learn or remember things. > Existing mental health problems will be made worse by using cannabis. Cannabis can also trigger serious mental health problems, in some people (eg. people who have had mental health problems before, or who have a history of mental problems in their family).
? difficultes de concentration, difficultes scolaires... ; 集中力の欠如 学力低下 ? dependance psychique parfois constatee lors d’une consommation reguliere et frequente : 継続的に使用した場合の精神的依存症状 preoccupations centrees sur l’obtention du produit ; 大麻入手への執着 ? risques sociaux pour l’usager et son entourage lies aux contacts avec des circuits illicites pour se procurer le
produit ; 大麻使用と、入手の為に違法な経路と接触することによる社会的リスク ? chez certaines personnes plus fragiles, 耐性のない多くの使用者に関しては le cannabis peut declencher des hallucinations ou des modifications de perception et de prise de conscience d’
elles-memes : 幻覚や知覚の変化、人格の変化 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ dedoublement de la personnalite, sentiment de persecution. 精神の分裂、迫害妄想などがある ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Ces effets peuvent se traduire par une forte anxiete. これらの症状は激しい不安感に起因する
マリファナは精神病のリスクを増加させる Marijuana use boosts risk of psychosis: study (the Canadian Broadcasting Corporation - Radio Canada)
LONDON - Teens and young adults who frequently use marijuana are at higher risk of developing psychotic symptoms later in life, researchers say.
Dutch scientists studied 2,437 young people aged 14-24 to identify their predisposition to psychosis. Participants were questioned about their use of cannabis and followed for up to four years.
In the study, researchers used a broad definition of psychosis, ranging from occasionally hearing voices and paranoia to schizophrenia.
Jim van Os of the University of Maastricht in the Netherlands and his team found 21 per cent of cannabis users had experienced psychotic symptoms compared with 15 per cent among non-users.
This link has been documented in over 30 different scientific studies (studies done mostly in the UK, Australia and
Sweden) over the past 20 years. ----- Those who were heavy consumers of cannabis at age 18 were over 600% more likely to be diagnosed with schizophrenia
over the next 15 years than those did not take it. (see diagram below). Experts estimate that between 8% and 13% of all schizophrenia cases are
linked to marijuna / cannabis use during teen years. ----- Researchers in New Zealand found that those who used cannabis by the age of 15 were more than three times (300%) more likely to develop illnesses such as schizophrenia. Other research has backed this up, showing that cannabis use increases the risk of psychosis by up to 700 percent for heavy users, and that the risk increases in proportion to the amount of cannabis used (smoked or consumed). Additionally, the younger a person smokes/uses cannabis, the higher the risk for schizophrenia, and the worse the schizophrenia is when the person does develop it.
Research by psychiatrists in inner-city areas speak of cannabis being a factor in up to 80 percent of schizophrenia cases.
* A Swedish study of 50,000 military conscripts found heavy use of cannabis increased the risk of suicide by four times (400%). A Victorian study of 2332 adolescents found weekly use increased the risk of suicide attempts among females by five times. Weekly use as a teenager doubled the risk of depression and anxiety. Daily use at the age of 20 boosted the risk of depression and anxiety by five times (500%).
Using cannabis during adolescence or early adulthood increases the risk of developing psychotic symptoms, according to a study that tracked almost 2,500 young people. Crucially, those who are already predisposed to such problems are at a disproportionately greater risk when using the drug.
Psychiatrists found that those using cannabis have, on average, a 6% greater chance of suffering psychotic symptoms such as schizophrenia, delusions and paranoia, compared with those who don't take the drug. But for the 10% of people who are already vulnerable to such problems, such as those with a family history of schizophrenia, this figure leaps to 25%.
What's more, these figures depend on the level of drug intake, particularly for those already in danger, says Jim van Os of Maastricht University in the Netherlands, who led the study. "If you are vulnerable, then the more cannabis you use, the greater your risk of psychosis," he told a press conference in London on 1 December.
Overall, his team found that volunteers who were predisposed to mental problems and frequently smoked cannabis had roughly a 50% chance of suffering psychotic symptoms within the four years of the study, which took place in Germany.
Cannabis link to mental illness strengthened * 23:01 21 November 2002 Emma Young
The link between regular cannabis use and later depression and schizophrenia has been significantly strengthened by three new studies.
One of the key conclusions of the research is that people who start smoking cannabis as adolescents are at the greatest risk of later developing mental health problems. Another team calculates that eliminating cannabis use in the UK population could reduce cases of schizophrenia by 13 per cent.
Patton's team followed over 1600 Australian school pupils aged 14 to 15 for seven years. Daily cannabis use was associated with a five-fold increased risk of depression at the age of 20. Weekly use was linked to a two-fold increase. The regular users were no more likely to have suffered from depression or anxiety at the start of the study.
Finally, researchers led by Terrie Moffitt at King's College London, UK, analysed comprehensive data on over 1000 people born in Dunedin, New Zealand in 1972 and 1973. They found that people who used cannabis by age 15 were four times as likely to have a diagnosis of schizophreniform disorder (a milder version of schizophrenia) at age 26 than non-users.
Almost half of patients treated for a cannabis related mental disorder go on to develop a schizophrenic illness, a study has suggested. The Danish study, in the British Journal of Psychiatry, found a third of them developed paranoid schizophrenia.
The team from Aarhus Psychiatric Hospital obtained information on 535 patients treated for cannabis-induced psychotic symptoms from the Danish Psychiatric Central Register, who were then followed for three years. They were then compared to 2,721 people treated for schizophrenia-spectrum disorders who had no history of cannabis-induced illness. It was found that 44.5% of those with cannabis-induced psychotic symptoms went on to be diagnosed with schizophrenia-spectrum disorders.
Paul Corry, of the mental health charity Rethink, said: "This research reinforces our call for a public health information campaign about a drug which many young people still see as being risk free.
Prospective cohort study of cannabis use, predisposition for psychosis, and psychotic symptoms in young people
Participants 2437 young people (aged 14 to 24 years) with and without predisposition for psychosis.
Main outcome measure Psychotic symptoms at follow up as a function of cannabis use and predisposition for psychosis at baseline.
Results After adjustment for age, sex, socioeconomic status, urbanicity, childhood trauma, predisposition for psychosis at baseline, and use of other drugs, tobacco, and alcohol, cannabis use at baseline increased the cumulative incidence of psychotic symptoms at follow up four years later (adjusted odds ratio 1.67, 95% confidence interval 1.13 to 2.46). The effect of cannabis use was much stronger in those with any predisposition for psychosis at baseline (23.8% adjusted difference in risk, 95% confidence interval 7.9 to 39.7, P=0.003) than in those without (5.6%, 0.4 to 10.8, P=0.033). The risk difference in the "predisposition" group was significantly greater than the risk difference in the "no predisposition" group (test for interaction 18.2%, 1.6 to 34.8, P=0.032). There was a dose-response relation with increasing frequency of cannabis use. Predisposition for psychosis at baseline did not significantly predict cannabis use four years later (adjusted odds ratio 1.42, 95% confidence interval 0.88 to 2.31).
Conclusion Cannabis use moderately increases the risk of psychotic symptoms in young people but has a much stronger effect in those with evidence of predisposition for psychosis.
Women who smoke cannabis during pregnancy may be stunting the growth of their babies, research suggests. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The effect of one smoking one cannabis joint a week throughout pregnancy appears to be equivalent to the effect produced by smoking up to 15 cigarettes a day.
A team of researchers from the UK and New Zealand found no evidence that smoking cannabis when pregnant increases the risk of miscarriage.
But they did find that regular users were more likely to give birth to small babies.
However, the effect was small. On average, the babies of women who used cannabis at least once a week before and throughout pregnancy were 216g lighter than those of non-users.
They were also significantly shorter, and had smaller heads.
# Certaines etudes differencient les troubles en fonction de la periode d'exposition au cannabis. Ainsi, durant le premier trimestre de grossesse : troubles de la memoire ; durant le deuxieme trimestre : troubles de l'attention et impulsivite. 大麻使用時期により障害も変わるという多くの研究結果がる。妊娠初期1/3の期間は記憶障害、中期1/3の期間は注意力や衝動性 # D'autres auteurs montrent une augmentation des difficultes d'apprentissage de la lecture et du calcul, et des echecs scolaires deux fois plus frequents. 他の報告者は学力、文章力、計算力の低下、通常の2倍の落第率(義務教育でも落第がある)を指摘する。 # Et enfin, ces enfants sont plus souvent anxieux et depressifs. これらの子供たちは鬱や心配性であることが多い
Les effets actuellement documentes du cannabis sur le f?tus et l’enfant 現在資料に裏付けられた胎児と子供に対する大麻の影響 # A ce jour, il n'a pas ete demontre d'effet sur l'incidence des malformations congenitales, ni sur la prematurite. Une consommation reguliere tendrait toutefois a diminuer modestement le poids de naissance. 今日において大麻と先天的奇形や早産の関係は明らかになっていないが、定期的な大麻の使用は新生児の体重を減少させる # Les nouveau-nes de mere ayant consomme du cannabis pendant la grossesse presentent plus souvent des troubles du sommeil. 妊娠中に大麻を使用した母親の子供には睡眠障害がよくみられる # Au cours du premier mois, ils presentent plus de troubles du comportement : tremulations, diminution de la puissance des pleurs et de la reponse visuelle aux stimulations lumineuses. 一ヶ月目にふるえ、泣く力の減少、光の刺激に対する反応の減少などがみられる # Le cannabis exerce un effet negatif sur la croissance, visible entre 1 an et 9-12 ans : faible perimetre cranien. 大麻には成長に対する悪影響があり、1歳から9-12歳までの間に顕著である: 頭部の直径が小さい # Vers dix ans, les enfants exposes sont davantage hyperactifs, impulsifs et inattentifs. 10歳程度で注意欠陥多動性障害の傾向が出る。衝動的で不注意である。 # Ils presentent plus de troubles scolaires (meme si le QI est identique a celui des autres enfants) : diminution des capacites d'abstraction, du raisonnement en rapport avec la sphere visuelle. 学校内において多くの問題が生じる(IQが他の生徒と同じでも)。視覚的な抽象力、論理性が低下(?)
The Italian research team found that long-term learning in the rats was damaged by the cannabinoids irreversibly disrupting chemical and electrical processes in the brain during gestation. The exposed rats were also more hyperactive as infants, although this effect wore off as the rats reached adulthood.
"This is absolutely relevant," says Peter Fried, a psychologist at Carleton University in Ottawa, Canada, ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ who has done similar work in humans. "What they have found is very consistent with what we have found ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ in humans." ~~~~~~~~~~ The possible effects of maternal marijuana use on the unborn child and the child's later behaviour are controversial, say Cuomo and colleagues. They argue that rat studies can be very useful in assessing human effects, because studies of people can be hampered by complex confounding factors. These could include cigarette smoking, wealth or urban living.
In the study, pregnant rats were injected with a low dose of an artificial cannabinoid. Offspring exposed to the drug during gestation showed hyperactivity during infancy and adolescence, as measured by how many times they broke infrared beams crisscrossing their cages.
Fried told New Scientist that as well as affecting memory and learning, exposure to marijuana during pregnancy has a strong effect on visual mapping and analysis in human children.
The most commonly used illicit drug by women of reproductive age and by pregnant women is cannabis. There is not a great deal of research into the effects of cannabis on the development of the foetus but it is known that tetrahydrocannabinol (THC), the psychoactive component of cannabis, crosses the placenta in humans and is stored in the amniotic fluid that surrounds the baby.
Cannabis use during pregnancy has not been associated with birth abnormalities but it is considered harmful to the baby. There is some evidence that exposure to cannabis in the womb affects a baby's behaviour and may cause long-term behavioural problems.
Cannabis use during pregnancy is associated with premature labour and a minor reduction in birth weight. Low birth weight is related to an increased risk of infections and breathing problems. Breastfeeding
The THC in cannabis passes into the breast milk, attaches to the baby's fatty tissue and can stay in the baby's body for several weeks. It is believed that the drug may cause the baby to become unsettled and demand frequent feeding.
Research has found that babies who are exposed to cannabis in the womb may be irritable, unsettled and have feeding difficulties. These babies are more easily startled, have higher levels of tremors, may not see as well and have a high-pitched cry. These symptoms are no longer present one month after the birth. However, it appears that exposure to cannabis in the womb does affect some aspects of behaviour beyond the baby stage.
Children who have been exposed to cannabis in the womb have been observed to have more behavioural problems as toddlers than children who haven't been exposed to cannabis. They perform poorly on tasks of visual understanding, language comprehension, sustained attention and memory. In school, these children are more likely to experience difficulties in making decisions, remembering things and remaining attentive.
Tests of teenagers who were exposed to cannabis in the womb revealed significant reduction in attention, memory of visual stimuli, analysis and understanding.
Afghan Opium Cultivation, Cannabis Use Top Illicit Drug Problems
Cannabis is erroneously considered "a light drug," Costa said at a press conference on the release of the report. It is a serious problem because it is "a gate-opener for everything else."
Cannabis is not just a gateway, but a "dead end" for many people who then go on to use other drugs and use a variety of drugs, added John Walters, director of the White House Office of National Drug Control. He said that in the United States, the majority of people treated for dependency or abuse of illegal drugs are dependent on cannabis -- or marijuana, as it is called in the United States.
* YES. Among marijuana's most harmful consequences is its role in leading to the use of other illegal drugs like heroin and cocaine. Long-term studies of students who use drugs show that very few young people use other illegal drugs without first trying marijuana. While not all people who use marijuana go on to use other drugs, using marijuana sometimes lowers inhibitions about drug use and exposes users to a culture that encourages use of other drugs.
* The risk of using cocaine has been estimated to be more than 104 times greater for those who have tried marijuana than for those who have never tried it.
It's also important to realize that the campaign to allow marijuana to be used as medicine is a tactical maneuver in an overall strategy to completely legalize all drugs. Pro-legalization groups have transformed the debate from decriminalizing drug use to one of compassion and care for people with serious diseases. The New York Times interviewed Ethan Nadelman, Director of the Lindesmith Center, in January 2000. Responding to criticism from former Drug Czar Barry McCaffrey that the medical marijuana issue is a stalking-horse for drug legalization, Mr. Nadelman did not contradict General McCaffrey. "Will it help lead toward marijuana legaization?" Mr. Nadelman said: "I hope so."
CANNABIS IS ALSO OFTEN THE "GATEWAY DRUG" FOR A LARGE PROPORTION OF HEROIN USERS
Cannabis continues to be the primary drug of choice (followed by benzodiazepines) amongst 14 to 18 year old students (source: school surveys 1996, 1999, 2000). Studies in Sofia (source: Snowball sampling studies 1995, 1998) show that cannabis is also often the "gateway drug" for a large proportion of heroin users. At the same time according to available data from treatment demands and snowball sampling studies, heroin remains the main drug of regular misuse and dependence. The approximate number of regular heroin users in Bulgaria is in excess of 25 000-30 000. This number will be more accurate if the assumption is made that there are approximately the same number of people occasionally using (not in a regular base) heroin. Ethnographic studies and observations on the sites of dealing indicate that this approach is closer to the reality.
WHO DID NOT BOW TO POLITICAL PRESSURE IN PUBLISHING A REPORT ON CANNABIS (世界保健機構は大麻に関するレポートを提出するに際し、政治的圧力に屈しなかった)
The information contained in the final report reflects a summary of those aspects of the background papers which were considered to be scientifically sound. Section 13 refers to the analysis of the possibilities of comparing licit drugs, such as alcohol and tobacco, with cannabis.
However, the consensus was that due to lack of reliable epidemiological studies such comparisons ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ were more speculative than scientific. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ however, that the use of cannabis causes a number of health problems and that an increase in its use would make the situation worse.