simsenhor
04-03-2010, 16:41
Já vi tópicos do tipo Maconha x Cigarro, mas só c uns textos gigantes que ninguém lê... Então tá aí;
O único objetivo do tópico é esclarecer melhor os efeitos da maconha (droga usada como exemplo) comparada com outras drogas, criticando o preconceito que há em relação a esta, mas que NÃO EXISTE com alcool e cigarro.
Tecnicamente, para indivíduos maiores de idade, entre maconha, álcool e cigarro, a opção mais saudável é a primeira. Não necessariamente a mais segura. Já que maconha pode levar ao consumo de drogas mais pesadas e, por sua vez, mais prejudiciais a saúde.
http://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Rational_scale_to_assess_the_harm_of_drugs_%28mean _physical_harm_and_mean_dependence%29_pt.svg/380px-Rational_scale_to_assess_the_harm_of_drugs_%28mean _physical_harm_and_mean_dependence%29_pt.svg.png
Maconha em bolinhos (brownies), chás, etc... Não necessariamente o baseado.
Maconha medicinal:
Cidadezinha brasileira que cultivava maconha sem saber o que era (usava medicinalmente)
http://www.youtube.com/watch?v=5LXEV9tshWQ
5LXEV9tshWQ
01. Câncer
Costumamos ouvir que o consumo da Maconha em forma de “cigarro” – o famoso “baseado” – seria prejudicial à saúde, uma vez que causaria câncer nos pulmões, devido à fumaça. Isto não é verdade. A Associação Americana para Pesquisa do Câncer descobriu, em um de seus projetos, que a Maconha é capaz de desacelerar de maneira considerável o crescimento de tumuroes nos pulmões, seios e cérebro.
02. Crises convulsivas
A maconha, vista como relaxante muscular, é um ótimo “remédio” em casos de pessoas que sofrem convulsões. Atualmente, existem relatos provando que, em alguns casos, a “Cannabis sativa” foi a única responsável no combate a estas crises.
03. Enxaqueca / Fortes dores de cabeça
Desde que a Maconha medicinal foi legalizada na Califórnia, há relatos médicos de mais de 300 mil pessoas que antes sofriam de enxaqueca e hoje conseguem aliviar e/ou tratar deste problema com o uso prescrito pelos médicos.
04. Glaucoma
O glaucoma é o aumento da pressão intra-ocular onde o nervo óptico é prejudicado. Também utilizada em pacientes que sofrem deste mal, não há um único relato onde a Maconha não foi eficaz no tratamento.
05. Esclerose Múltipla
Relatos vêm sendo criados sobre o poderoso benefício proporcionado pela Maconha nos tratamentos de esclerose múltipla, onde um dos casos mais famosos é o do ex-apresentador Montel Williams. A marijuana age diretamente contra os efeitos neurológicos e espasmos musculares causados pela doença fatal.
06. Tourette e TOC
Assim como nos tratamentos contra convulções e esclerose múltima, a Maconha vem apresentando, ao longo do tempo, um excelente resultado frente à Síndrome de Tourette e ao Transtorno Obsessivo-Compultivo (TOC).
07. ADD / ADHD / TDAH
Em um estudo recente realizado nos Estados Unidos, constatou-se que a Maconha não só é uma ótima alternativa à Ritalina, como também não apresenta os efeitos colaterais causados pelos medicamento farmacêutico.
08. Doenças crônicas
A Maconha também vem sido recomendada no tratamento de doenças crônicas, como em caso de náuseas, dores abdominais e diarréia.
09. Mal de Alzheimer
Apesar de todos os rumores que circulam sobre o efeito da Maconha no cérebro, o Scripps Institute, nos Estados Unidos, provou, em 2006, que o THD encontrado na Cannabis sativa é altamente preventivo quanto ao Mal de Alzheimer.
10. Tensão Pré-Menstrual (TPM)
Assim como no tratamento de doenças crônicas, a Maconha é um excelente remédio para aquelas que sofrem na TPM, sendo pra lá de eficaz no alívio das dores provocadas pela cólica.
Sobre o gráfico:
O gráfico tá na wikipedia, é de uma pesquisa da The Lancelot:
Drug misuse and abuse are major health problems. Harmful drugs are regulated according to classification systems that purport to relate to the harms and risks of each drug. However, the methodology and processes underlying classification systems are generally neither specified nor transparent, which reduces confidence in their accuracy and undermines health education messages. We developed and explored the feasibility of the use of a nine-category matrix of harm, with an expert delphic procedure, to assess the harms of a range of illicit drugs in an evidence-based fashion. We also included five legal drugs of misuse (alcohol, khat, solvents, alkyl nitrites, and tobacco) and one that has since been classified (ketamine) for reference. The process proved practicable, and yielded roughly similar scores and rankings of drug harm when used by two separate groups of experts. The ranking of drugs produced by our assessment of harm differed from those used by current regulatory systems. Our methodology offers a systematic framework and process that could be used by national and international regulatory bodies to assess the harm of current and future drugs of abuse.
Sobre a liberação da maconha:
Entrevista da TV BRASIL, que aborda também os testes realizados pela Holanda (nas outras partes do programa):
http://www.youtube.com/watch?v=feu3WzGT1UM
feu3WzGT1UM
Agora aqueles textos chatos, pra quem estiver interessado;
Efeitos a longo prazo da maconha na saúde mental do indivíduo:
http://en.wikipedia.org/wiki/Long-term_effects_of_cannabis#Mental_health
Cannabis use has been assessed by several studies[27] to be correlated with the development of anxiety, psychosis, and depression.[28][29] Some studies assess that the causality is more likely to involve a path from cannabis use to psychotic symptoms rather than a path from psychotic symptoms to cannabis use,[30] while others assess the opposite direction of the causality, or hold cannabis to only form parts of the "causal constellation", while not inflicting mental health problems that would have occurred in the absence of the cannabis use.[31][32] A common interpretation of the correlation and theorized direction of the causality is the self-medication hypothesis, which is based on partially or fully attributing the correlation between psychiatric diseases and cannabis to the extensive substance abuse among sufferers of certain mental disorders, before diagnosis in many cases, which increases the likeliness of cannabis use among the mentally ill and the undiagnosed, thus accounting for correlation and debunking some claims of causality with the opposite direction.[33] As much as 60% of the mentally ill are suspected to be substance abusers, and many seem to prefer cannabis and alcohol.[34] Dr Stanley Zammit of Bristol and Cardiff universities (in the Daily Express newspaper of the 27th of July 2007) reported, "Even if cannabis did increase the risk of psychosis, most people using the drug would not get ill" But he added: "Nevertheless, we would still advise people to avoid or limit their use of this drug, especially if they start to develop any mental health symptoms or if they have relatives with psychotic illnesses." A 2007 study of studies published in the Lancet concluded that cannabis users are 40% more likely to be sufferers of a psychotic illness than non-users.[35]
A large, unselected population-based study, published in British Journal of Psychiatry (2008), examined cannabis use and prodromal symptoms of psychosis at age 15–16 years and conclude that cannabis use is associated with prodromal symptoms of psychosis in adolescence.[36]
The direction of causation was more directly examined in a study by Dr. Mikkel Arendt of Aarhus University in Risskov, Denmark, and colleagues, which found that individuals treated for psychotic episodes following cannabis use had the same likelihood of having a mother, sister or other "first-degree" relative with schizophrenia as did the individuals who had actually been treated for schizophrenia themselves. This suggests that the psychosis blamed on cannabis use is in fact the result of a genetic predisposition towards schizophrenia. "These people would have developed schizophrenia whether or not they used cannabis"[37]
In a recent study at the Institute of Psychiatry at King's College London, scientists have confirmed a link between potent cannabis use ("skunk" cannabis, which accounts for 80 per cent of street seizures of the drug in the UK[38]) and transient psychotic symptoms in healthy people. After testing 22 healthy males in their late 20s by injecting them with THC, with a control dummy injection administered to a percentage of the sample group, a link was found between the chemical and psychosis, "in which hallucinations leave sufferers unable to know what is real and what is imagined". Dr Paul Morrison, who lead the team, concluded, "these findings confirm that THC can induce a transient acute psychological reaction in psychiatrically well individuals"[38]. In addition, it was found that the extent of the psychotic reaction was not related to "the degree of anxiety or cognitive impairment" in the sample group. Further research is needed into the chemical makeup of skunk cannabis as it is believed stronger strains have virtually no traces of CBD (cannabidiol), which appears to counteract the damaging effects of THC.[38] However, there is likely to be wide variation in the THC and CBD levels (and ratios) since numerous (perhaps even hundreds) of different strains of cannabis have been marketed by dealers as "skunk," some of which are descended from the original 1980s Amsterdam variety.
The BEACH[39] study (Bettering the Evaluation and Care of Health) conducted by the Australian General Practice Statistics and Classification Centre, based at the University of Sydney, found that "cannabis smokers are more likely to suffer depression, anxiety and psychosis". The report continues that of the number of patients who mentioned cannabis use to their GP, 48% had a psychological problem, including 19% with depression, 9% with psychosis and 6% had anxiety.[40] However, it was also noted that few cannabis users actually tell their doctors that they use it, which could potentially bias the results of the study. Much of the evidence for a short-lived cannabis psychosis is largely based on case reports where heavy cannabis use has preceded the onset of a psychotic episode, which then remits on abstinence.[41] Depictions of a toxic or acute cannabis psychosis have been reported in a number of countries such as New Zealand[42], South Africa[43], Sweden[44] and the UK.[45]
The largest longitudinal study examining the link between cannabis and psychosis was undertaken by Andreasson and colleagues [46] and followed 45,570 male Swedish Army conscripts for 15 years. After controlling for other factors such as parental mental illness or a pre-existing psychotic illnes at conscription, the study found that the odds of developing schizophrenia later in life were "1.5 times higher for those who had used cannabis 1-10 times and 2.3 times more likely for those who had used cannabis 10 times or more".[47] Further to criticism that the study did not control for the use of other potentially psychotogenic substances such as amphetamines, a follow-up study re-analysed the data and ruled out this argument, finding that cannabis use remained predictive of schizophrenia in a dose-dependent manner even after accounting for other substance use and pre-morbid social integration.[48]
Research findings from the University of Melbourne and the [Orygen Research Centre], reported in New Scientist[49] reveal links between heavy cannabis use and brain size. In this study to determine whether long-term and heavy cannabis use is associated with gross anatomical abnormalities in two regions of the brain that are particularly rich in cannabinoid receptors, researchers found that the brain scans of 15 heavy users, who had smoked at least five joints a day for over 10 years, showed that on average the hippocampus and amygdales of the test group were 12% and 7.1% smaller than non-users, respectively. According to commentary provided by the National Cannabis Prevention and Information Centre, these brain regions are intricately involved in learning and memory processes and are considered core components of the emotional brain and the research found that in addition left hippocampal and amygdala volume was inversely associated with cumulative doses of cannabis over the previous 10 years, as well as subthreshold positive psychotic symptoms. In their commentary, NCPIC state: "While modest use may not lead to significant neurotoxicity, these results corroborate similar findings within the animal literature and indicate that heavy daily cannabis use over protracted periods exerts harmful effects on brain tissue and mental health".[50]
Less attention has been given to the association between cannabis use and depression, though it is possible this is because cannabis users who suffer from depression are less likely to access treatment than those suffering from psychosis.[51] Chen and colleagues (2002) re-analyzed the US National Comorbidity Survey (NCS) to examine the relationship between cannabis use and a major depressive episode and discovered that some degree of cannabis dependence was associated with a 3.4 time greater risk of major depression.[52] Similarly, data retrieved from the US Longitudinal Alcohol Epidemiologic Survey showed that cannabis dependency within the past year was associated with a 6.4 fold chance of also receiving a diagnosis for major depression in that time.[53] The issue of suicide and cannabis use is considered by Borges, Walters, and Kessler who examined whether cannabis use heightens the risk of suicide or attempted suicide. Cross-sectional data from the US National Comorbidity Survey indicated that cannabis-dependent individuals were 2.4 times more likely to report a suicide attempt than non-cannabis-dependent individuals, after controlling for socio-demographic factors, psychiatric disorders and other drug use.[54] Beautrais et al. (1999) examined 302 hospitalized cases of suicide attempts and found that 16% screened positive for cannabis abuse or dependence, compared with 2% of a random community sample. After controlling for depression and social disadvantage the study found this translated to a two-fold suicide attempt risk for those who had a cannabis use disorder.[55]
[edit] Co-occurrence of mental illness
A 2005 meta analysis of available data which evaluated several hypotheses regarding the correlation of cannabis and psychosis found that there is no support for the hypothesis that cannabis can cause cases of psychosis which would not have occurred otherwise, however further study is needed to explore the correlation between cannabis and other types of psychosis patients.[56] Studies have shown that a risk does exist in some individuals with a predisposition to mental illness to develop symptoms of psychosis.[28] The risk was found to be directly related to high dosage and frequency of use, early age of introduction to the drug, and was especially pronounced for those with a predisposition for mental illness. These results have been questioned as being biased by failing to account for medicinal versus recreational usage[57] — critics contend it could be a causal relationship, or it could be that people who are susceptible to mental problems tend to smoke cannabis, or it could be connected to the criminalization of cannabis. Another important question is whether the observed symptoms of mental illness are actually connected to development of a permanent mental disorder; cannabis may trigger latent conditions, or be part of a complex coordination of causes of mental illness, referred to in psychology as the diathesis-stress model. People with developed psychological disorders are known to self-medicate their symptoms with cannabis as well, although one study has claimed that those with a predisposition for psychosis did not show a statistically significant increase in likelihood of cannabis use four years later.[28]
A 2005 literature review of the use of cannabis in mental health patients found that the drug can have very different effects on different patients. Although "no controlled trials of THC have been done in bipolar disorder," there is anecdotal evidence that "for some people marijuana is beneficial" as a treatment for bipolar disorder. The reviewers suggested that randomized studies and standardized administration techniques would be required to create conclusive evidence.[58]
[edit] Correlation versus causation
Main article: Correlation does not imply causation
Some studies conclude that there is a correlation of cannabis use and some symptoms of psychosis, but do not necessarily support the notion that cannabis use is a sufficient or necessary cause for psychosis. It might be a component cause, part of a complex constellation of factors leading to psychosis, or it might be a correlation without forward causality at all.
For example, a review of the evidence by Louise Arsenault, et al., in 2004 reports that on an individual level, cannabis use confers an overall twofold increase in the relative risk of later schizophrenia, assuming a causal relationship. This same research also states that "There is little dispute that cannabis intoxication can lead to acute transient psychotic episodes in some individuals". The study synthesizes the results of several studies into a statistical model. The study does not correct for the use of other illicit drugs, and relies on self-reporting of cannabis dosage. The study also does not determine if the cannabis use preceded or followed the mental health problem.[32]
Similarly, the landmark study, in 1987, of 50,000 Swedish Army conscripts, mentioned earlier, found that those who admitted at age 18 to having taken cannabis on more than 50 occasions, were six times more likely to develop schizophrenia in the following 15 years. In fact, psychosis cases were restricted to patients requiring a hospital admission. These findings have not been replicated in another population based sample. As the study did not control for symptoms preexisting onset of cannabis use, the use of other illicit drugs, the study does not resolve the correlation versus causality question but has fueled a major debate within the scientific community. This study also used self reporting for cannabis dosage.[59]
A 2005 study found that "the onset of schizotypal symptoms generally precedes the onset of cannabis use. The findings do not support a causal link between cannabis use and schizotypal traits".[60] A schizotypal personality disorder is a personality disorder different from schizophrenia, though there is some evidence that the former may predispose to the latter. A 2007 British study concluded, "We found few appreciable differences in symptomatology between schizophrenic patients who were or were not cannabis users. There were no differences in the proportion of people with a positive family history of schizophrenia between cannabis users and non-users. This argues against a distinct schizophrenia-like psychosis caused by cannabis."[61]
Research based on the Dunedin Multidisciplinary Health and Development Study has found that those who begin regular use of cannabis in early adolescence (from age 15, median 25 days per year by age 18) and also fit a certain genetic profile (specifically, the Val/Val variant of the COMT gene) are five times more likely to develop psychotic illnesses than individuals with differing genotypes, or those who do not use cannabis.[62][63] The study was noted for having controlled for preexisting symptoms, but is open to the criticism that it cannot control for late adolescent onset of psychotic illness. Also, the study was on a cohort population, so there is no way to correlate a change in the rate of adolescent use with a change in the rate of incidence of schizophrenia in the study population. These points undermine its value in resolving the correlation versus causality question.
A study that inversely correlated cerebrospinal anandamide (an endogenous cannabinoid) levels with severity of schizophrenia (i.e., that anandamide was released in order to suppress psychosis) suggests that cannabis use may be an effect of schizophrenia or its predisposition, as opposed to a cause.[64]
The prevalence of cannabis use has increased substantially during the last decades whereas the prevalence of psychotic illness suggests no causal relationship.[56]
[edit] Cannabidiol and schizophrenia
A recent study has shown that cannabidiol (a major constituent of cannabis) may be as effective as atypical antipsychotics in treating schizophrenia,[65] Further research has verified these results. Leweke et al., (2009) performed a double blind, 4 week, explorative study controlled clinical trial, to compare the effects of purified cannabidiol and the atypical antipsychotic amisulpride on improving the symptoms of schizophrenia in 42 patients with acute paranoid schizophrenia. 'Both treatments were associated with a significant decrease of psychotic symptoms after 2 and 4 weeks as assessed by BPRS and PANSS. However, there was no statistical difference between both treatment groups. In contrast, cannabidiol induced significantly less side effects (EPS, increase in prolactin, weight gain) when compared to amisulpride'.[66] The authors conclude cannabidiol revealed substantial antipsychotic properties in acute paranoid schizophirenia (Leweke et al., 2009). This led the authors to suggest the endocannabinoid system plays an adaptive role in the development of paranoid schizophirenia and that this research provides evidence that this mechanism may be a valuable target for 'antipsychotic treament strategies' .[66]
A 2008 study published in the British Journal of Psychiatry showed significant differences in Oxford-Liverpool Inventory of Feelings and Experiences scores between three groups: The first consisted of non-cannabis users, the second of users who tested positive for Δ9-THC only, and the third consisted of users who tested positive for both Δ9-THC and CBD. The Δ9-THC only subset scored significantly higher for unusual experiences, while users of both Δ9-THC and CBD had much lower introvertive anhedonia scores .[67]
Tem também uma reportagem bem interessante passando na GNT sobre os efeitos da maconha na saúde mental do indivíduo menor de idade. E são bem graves. Não lembro dos dados, mas a taxa de jovens com menos de 15 anos que já experimentaram a maconha no Reino Unido é de mais de 40%!!!
Lá existem lojas especializadas, que vendem bolinhos, cachimbos, tudo que você possa imaginar de maconha. Quem tem licensa, pode comprar.
O único objetivo do tópico é esclarecer melhor os efeitos da maconha (droga usada como exemplo) comparada com outras drogas, criticando o preconceito que há em relação a esta, mas que NÃO EXISTE com alcool e cigarro.
Tecnicamente, para indivíduos maiores de idade, entre maconha, álcool e cigarro, a opção mais saudável é a primeira. Não necessariamente a mais segura. Já que maconha pode levar ao consumo de drogas mais pesadas e, por sua vez, mais prejudiciais a saúde.
http://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Rational_scale_to_assess_the_harm_of_drugs_%28mean _physical_harm_and_mean_dependence%29_pt.svg/380px-Rational_scale_to_assess_the_harm_of_drugs_%28mean _physical_harm_and_mean_dependence%29_pt.svg.png
Maconha em bolinhos (brownies), chás, etc... Não necessariamente o baseado.
Maconha medicinal:
Cidadezinha brasileira que cultivava maconha sem saber o que era (usava medicinalmente)
http://www.youtube.com/watch?v=5LXEV9tshWQ
5LXEV9tshWQ
01. Câncer
Costumamos ouvir que o consumo da Maconha em forma de “cigarro” – o famoso “baseado” – seria prejudicial à saúde, uma vez que causaria câncer nos pulmões, devido à fumaça. Isto não é verdade. A Associação Americana para Pesquisa do Câncer descobriu, em um de seus projetos, que a Maconha é capaz de desacelerar de maneira considerável o crescimento de tumuroes nos pulmões, seios e cérebro.
02. Crises convulsivas
A maconha, vista como relaxante muscular, é um ótimo “remédio” em casos de pessoas que sofrem convulsões. Atualmente, existem relatos provando que, em alguns casos, a “Cannabis sativa” foi a única responsável no combate a estas crises.
03. Enxaqueca / Fortes dores de cabeça
Desde que a Maconha medicinal foi legalizada na Califórnia, há relatos médicos de mais de 300 mil pessoas que antes sofriam de enxaqueca e hoje conseguem aliviar e/ou tratar deste problema com o uso prescrito pelos médicos.
04. Glaucoma
O glaucoma é o aumento da pressão intra-ocular onde o nervo óptico é prejudicado. Também utilizada em pacientes que sofrem deste mal, não há um único relato onde a Maconha não foi eficaz no tratamento.
05. Esclerose Múltipla
Relatos vêm sendo criados sobre o poderoso benefício proporcionado pela Maconha nos tratamentos de esclerose múltipla, onde um dos casos mais famosos é o do ex-apresentador Montel Williams. A marijuana age diretamente contra os efeitos neurológicos e espasmos musculares causados pela doença fatal.
06. Tourette e TOC
Assim como nos tratamentos contra convulções e esclerose múltima, a Maconha vem apresentando, ao longo do tempo, um excelente resultado frente à Síndrome de Tourette e ao Transtorno Obsessivo-Compultivo (TOC).
07. ADD / ADHD / TDAH
Em um estudo recente realizado nos Estados Unidos, constatou-se que a Maconha não só é uma ótima alternativa à Ritalina, como também não apresenta os efeitos colaterais causados pelos medicamento farmacêutico.
08. Doenças crônicas
A Maconha também vem sido recomendada no tratamento de doenças crônicas, como em caso de náuseas, dores abdominais e diarréia.
09. Mal de Alzheimer
Apesar de todos os rumores que circulam sobre o efeito da Maconha no cérebro, o Scripps Institute, nos Estados Unidos, provou, em 2006, que o THD encontrado na Cannabis sativa é altamente preventivo quanto ao Mal de Alzheimer.
10. Tensão Pré-Menstrual (TPM)
Assim como no tratamento de doenças crônicas, a Maconha é um excelente remédio para aquelas que sofrem na TPM, sendo pra lá de eficaz no alívio das dores provocadas pela cólica.
Sobre o gráfico:
O gráfico tá na wikipedia, é de uma pesquisa da The Lancelot:
Drug misuse and abuse are major health problems. Harmful drugs are regulated according to classification systems that purport to relate to the harms and risks of each drug. However, the methodology and processes underlying classification systems are generally neither specified nor transparent, which reduces confidence in their accuracy and undermines health education messages. We developed and explored the feasibility of the use of a nine-category matrix of harm, with an expert delphic procedure, to assess the harms of a range of illicit drugs in an evidence-based fashion. We also included five legal drugs of misuse (alcohol, khat, solvents, alkyl nitrites, and tobacco) and one that has since been classified (ketamine) for reference. The process proved practicable, and yielded roughly similar scores and rankings of drug harm when used by two separate groups of experts. The ranking of drugs produced by our assessment of harm differed from those used by current regulatory systems. Our methodology offers a systematic framework and process that could be used by national and international regulatory bodies to assess the harm of current and future drugs of abuse.
Sobre a liberação da maconha:
Entrevista da TV BRASIL, que aborda também os testes realizados pela Holanda (nas outras partes do programa):
http://www.youtube.com/watch?v=feu3WzGT1UM
feu3WzGT1UM
Agora aqueles textos chatos, pra quem estiver interessado;
Efeitos a longo prazo da maconha na saúde mental do indivíduo:
http://en.wikipedia.org/wiki/Long-term_effects_of_cannabis#Mental_health
Cannabis use has been assessed by several studies[27] to be correlated with the development of anxiety, psychosis, and depression.[28][29] Some studies assess that the causality is more likely to involve a path from cannabis use to psychotic symptoms rather than a path from psychotic symptoms to cannabis use,[30] while others assess the opposite direction of the causality, or hold cannabis to only form parts of the "causal constellation", while not inflicting mental health problems that would have occurred in the absence of the cannabis use.[31][32] A common interpretation of the correlation and theorized direction of the causality is the self-medication hypothesis, which is based on partially or fully attributing the correlation between psychiatric diseases and cannabis to the extensive substance abuse among sufferers of certain mental disorders, before diagnosis in many cases, which increases the likeliness of cannabis use among the mentally ill and the undiagnosed, thus accounting for correlation and debunking some claims of causality with the opposite direction.[33] As much as 60% of the mentally ill are suspected to be substance abusers, and many seem to prefer cannabis and alcohol.[34] Dr Stanley Zammit of Bristol and Cardiff universities (in the Daily Express newspaper of the 27th of July 2007) reported, "Even if cannabis did increase the risk of psychosis, most people using the drug would not get ill" But he added: "Nevertheless, we would still advise people to avoid or limit their use of this drug, especially if they start to develop any mental health symptoms or if they have relatives with psychotic illnesses." A 2007 study of studies published in the Lancet concluded that cannabis users are 40% more likely to be sufferers of a psychotic illness than non-users.[35]
A large, unselected population-based study, published in British Journal of Psychiatry (2008), examined cannabis use and prodromal symptoms of psychosis at age 15–16 years and conclude that cannabis use is associated with prodromal symptoms of psychosis in adolescence.[36]
The direction of causation was more directly examined in a study by Dr. Mikkel Arendt of Aarhus University in Risskov, Denmark, and colleagues, which found that individuals treated for psychotic episodes following cannabis use had the same likelihood of having a mother, sister or other "first-degree" relative with schizophrenia as did the individuals who had actually been treated for schizophrenia themselves. This suggests that the psychosis blamed on cannabis use is in fact the result of a genetic predisposition towards schizophrenia. "These people would have developed schizophrenia whether or not they used cannabis"[37]
In a recent study at the Institute of Psychiatry at King's College London, scientists have confirmed a link between potent cannabis use ("skunk" cannabis, which accounts for 80 per cent of street seizures of the drug in the UK[38]) and transient psychotic symptoms in healthy people. After testing 22 healthy males in their late 20s by injecting them with THC, with a control dummy injection administered to a percentage of the sample group, a link was found between the chemical and psychosis, "in which hallucinations leave sufferers unable to know what is real and what is imagined". Dr Paul Morrison, who lead the team, concluded, "these findings confirm that THC can induce a transient acute psychological reaction in psychiatrically well individuals"[38]. In addition, it was found that the extent of the psychotic reaction was not related to "the degree of anxiety or cognitive impairment" in the sample group. Further research is needed into the chemical makeup of skunk cannabis as it is believed stronger strains have virtually no traces of CBD (cannabidiol), which appears to counteract the damaging effects of THC.[38] However, there is likely to be wide variation in the THC and CBD levels (and ratios) since numerous (perhaps even hundreds) of different strains of cannabis have been marketed by dealers as "skunk," some of which are descended from the original 1980s Amsterdam variety.
The BEACH[39] study (Bettering the Evaluation and Care of Health) conducted by the Australian General Practice Statistics and Classification Centre, based at the University of Sydney, found that "cannabis smokers are more likely to suffer depression, anxiety and psychosis". The report continues that of the number of patients who mentioned cannabis use to their GP, 48% had a psychological problem, including 19% with depression, 9% with psychosis and 6% had anxiety.[40] However, it was also noted that few cannabis users actually tell their doctors that they use it, which could potentially bias the results of the study. Much of the evidence for a short-lived cannabis psychosis is largely based on case reports where heavy cannabis use has preceded the onset of a psychotic episode, which then remits on abstinence.[41] Depictions of a toxic or acute cannabis psychosis have been reported in a number of countries such as New Zealand[42], South Africa[43], Sweden[44] and the UK.[45]
The largest longitudinal study examining the link between cannabis and psychosis was undertaken by Andreasson and colleagues [46] and followed 45,570 male Swedish Army conscripts for 15 years. After controlling for other factors such as parental mental illness or a pre-existing psychotic illnes at conscription, the study found that the odds of developing schizophrenia later in life were "1.5 times higher for those who had used cannabis 1-10 times and 2.3 times more likely for those who had used cannabis 10 times or more".[47] Further to criticism that the study did not control for the use of other potentially psychotogenic substances such as amphetamines, a follow-up study re-analysed the data and ruled out this argument, finding that cannabis use remained predictive of schizophrenia in a dose-dependent manner even after accounting for other substance use and pre-morbid social integration.[48]
Research findings from the University of Melbourne and the [Orygen Research Centre], reported in New Scientist[49] reveal links between heavy cannabis use and brain size. In this study to determine whether long-term and heavy cannabis use is associated with gross anatomical abnormalities in two regions of the brain that are particularly rich in cannabinoid receptors, researchers found that the brain scans of 15 heavy users, who had smoked at least five joints a day for over 10 years, showed that on average the hippocampus and amygdales of the test group were 12% and 7.1% smaller than non-users, respectively. According to commentary provided by the National Cannabis Prevention and Information Centre, these brain regions are intricately involved in learning and memory processes and are considered core components of the emotional brain and the research found that in addition left hippocampal and amygdala volume was inversely associated with cumulative doses of cannabis over the previous 10 years, as well as subthreshold positive psychotic symptoms. In their commentary, NCPIC state: "While modest use may not lead to significant neurotoxicity, these results corroborate similar findings within the animal literature and indicate that heavy daily cannabis use over protracted periods exerts harmful effects on brain tissue and mental health".[50]
Less attention has been given to the association between cannabis use and depression, though it is possible this is because cannabis users who suffer from depression are less likely to access treatment than those suffering from psychosis.[51] Chen and colleagues (2002) re-analyzed the US National Comorbidity Survey (NCS) to examine the relationship between cannabis use and a major depressive episode and discovered that some degree of cannabis dependence was associated with a 3.4 time greater risk of major depression.[52] Similarly, data retrieved from the US Longitudinal Alcohol Epidemiologic Survey showed that cannabis dependency within the past year was associated with a 6.4 fold chance of also receiving a diagnosis for major depression in that time.[53] The issue of suicide and cannabis use is considered by Borges, Walters, and Kessler who examined whether cannabis use heightens the risk of suicide or attempted suicide. Cross-sectional data from the US National Comorbidity Survey indicated that cannabis-dependent individuals were 2.4 times more likely to report a suicide attempt than non-cannabis-dependent individuals, after controlling for socio-demographic factors, psychiatric disorders and other drug use.[54] Beautrais et al. (1999) examined 302 hospitalized cases of suicide attempts and found that 16% screened positive for cannabis abuse or dependence, compared with 2% of a random community sample. After controlling for depression and social disadvantage the study found this translated to a two-fold suicide attempt risk for those who had a cannabis use disorder.[55]
[edit] Co-occurrence of mental illness
A 2005 meta analysis of available data which evaluated several hypotheses regarding the correlation of cannabis and psychosis found that there is no support for the hypothesis that cannabis can cause cases of psychosis which would not have occurred otherwise, however further study is needed to explore the correlation between cannabis and other types of psychosis patients.[56] Studies have shown that a risk does exist in some individuals with a predisposition to mental illness to develop symptoms of psychosis.[28] The risk was found to be directly related to high dosage and frequency of use, early age of introduction to the drug, and was especially pronounced for those with a predisposition for mental illness. These results have been questioned as being biased by failing to account for medicinal versus recreational usage[57] — critics contend it could be a causal relationship, or it could be that people who are susceptible to mental problems tend to smoke cannabis, or it could be connected to the criminalization of cannabis. Another important question is whether the observed symptoms of mental illness are actually connected to development of a permanent mental disorder; cannabis may trigger latent conditions, or be part of a complex coordination of causes of mental illness, referred to in psychology as the diathesis-stress model. People with developed psychological disorders are known to self-medicate their symptoms with cannabis as well, although one study has claimed that those with a predisposition for psychosis did not show a statistically significant increase in likelihood of cannabis use four years later.[28]
A 2005 literature review of the use of cannabis in mental health patients found that the drug can have very different effects on different patients. Although "no controlled trials of THC have been done in bipolar disorder," there is anecdotal evidence that "for some people marijuana is beneficial" as a treatment for bipolar disorder. The reviewers suggested that randomized studies and standardized administration techniques would be required to create conclusive evidence.[58]
[edit] Correlation versus causation
Main article: Correlation does not imply causation
Some studies conclude that there is a correlation of cannabis use and some symptoms of psychosis, but do not necessarily support the notion that cannabis use is a sufficient or necessary cause for psychosis. It might be a component cause, part of a complex constellation of factors leading to psychosis, or it might be a correlation without forward causality at all.
For example, a review of the evidence by Louise Arsenault, et al., in 2004 reports that on an individual level, cannabis use confers an overall twofold increase in the relative risk of later schizophrenia, assuming a causal relationship. This same research also states that "There is little dispute that cannabis intoxication can lead to acute transient psychotic episodes in some individuals". The study synthesizes the results of several studies into a statistical model. The study does not correct for the use of other illicit drugs, and relies on self-reporting of cannabis dosage. The study also does not determine if the cannabis use preceded or followed the mental health problem.[32]
Similarly, the landmark study, in 1987, of 50,000 Swedish Army conscripts, mentioned earlier, found that those who admitted at age 18 to having taken cannabis on more than 50 occasions, were six times more likely to develop schizophrenia in the following 15 years. In fact, psychosis cases were restricted to patients requiring a hospital admission. These findings have not been replicated in another population based sample. As the study did not control for symptoms preexisting onset of cannabis use, the use of other illicit drugs, the study does not resolve the correlation versus causality question but has fueled a major debate within the scientific community. This study also used self reporting for cannabis dosage.[59]
A 2005 study found that "the onset of schizotypal symptoms generally precedes the onset of cannabis use. The findings do not support a causal link between cannabis use and schizotypal traits".[60] A schizotypal personality disorder is a personality disorder different from schizophrenia, though there is some evidence that the former may predispose to the latter. A 2007 British study concluded, "We found few appreciable differences in symptomatology between schizophrenic patients who were or were not cannabis users. There were no differences in the proportion of people with a positive family history of schizophrenia between cannabis users and non-users. This argues against a distinct schizophrenia-like psychosis caused by cannabis."[61]
Research based on the Dunedin Multidisciplinary Health and Development Study has found that those who begin regular use of cannabis in early adolescence (from age 15, median 25 days per year by age 18) and also fit a certain genetic profile (specifically, the Val/Val variant of the COMT gene) are five times more likely to develop psychotic illnesses than individuals with differing genotypes, or those who do not use cannabis.[62][63] The study was noted for having controlled for preexisting symptoms, but is open to the criticism that it cannot control for late adolescent onset of psychotic illness. Also, the study was on a cohort population, so there is no way to correlate a change in the rate of adolescent use with a change in the rate of incidence of schizophrenia in the study population. These points undermine its value in resolving the correlation versus causality question.
A study that inversely correlated cerebrospinal anandamide (an endogenous cannabinoid) levels with severity of schizophrenia (i.e., that anandamide was released in order to suppress psychosis) suggests that cannabis use may be an effect of schizophrenia or its predisposition, as opposed to a cause.[64]
The prevalence of cannabis use has increased substantially during the last decades whereas the prevalence of psychotic illness suggests no causal relationship.[56]
[edit] Cannabidiol and schizophrenia
A recent study has shown that cannabidiol (a major constituent of cannabis) may be as effective as atypical antipsychotics in treating schizophrenia,[65] Further research has verified these results. Leweke et al., (2009) performed a double blind, 4 week, explorative study controlled clinical trial, to compare the effects of purified cannabidiol and the atypical antipsychotic amisulpride on improving the symptoms of schizophrenia in 42 patients with acute paranoid schizophrenia. 'Both treatments were associated with a significant decrease of psychotic symptoms after 2 and 4 weeks as assessed by BPRS and PANSS. However, there was no statistical difference between both treatment groups. In contrast, cannabidiol induced significantly less side effects (EPS, increase in prolactin, weight gain) when compared to amisulpride'.[66] The authors conclude cannabidiol revealed substantial antipsychotic properties in acute paranoid schizophirenia (Leweke et al., 2009). This led the authors to suggest the endocannabinoid system plays an adaptive role in the development of paranoid schizophirenia and that this research provides evidence that this mechanism may be a valuable target for 'antipsychotic treament strategies' .[66]
A 2008 study published in the British Journal of Psychiatry showed significant differences in Oxford-Liverpool Inventory of Feelings and Experiences scores between three groups: The first consisted of non-cannabis users, the second of users who tested positive for Δ9-THC only, and the third consisted of users who tested positive for both Δ9-THC and CBD. The Δ9-THC only subset scored significantly higher for unusual experiences, while users of both Δ9-THC and CBD had much lower introvertive anhedonia scores .[67]
Tem também uma reportagem bem interessante passando na GNT sobre os efeitos da maconha na saúde mental do indivíduo menor de idade. E são bem graves. Não lembro dos dados, mas a taxa de jovens com menos de 15 anos que já experimentaram a maconha no Reino Unido é de mais de 40%!!!
Lá existem lojas especializadas, que vendem bolinhos, cachimbos, tudo que você possa imaginar de maconha. Quem tem licensa, pode comprar.