Effects
Cannabis has psychoactive and physiological effects when consumed. The minimum amount of THC required to have a perceptible psychoactive effect is about 10 micrograms per kilogram of body weight. Aside from a subjective change in perception and, most notably, mood, the most common short-term physical and neurological effects include increased heart rate, lowered blood pressure, impairment of short-term episodic memory, working memory, phsychomotor coordination, and concentration. Long-term effects are less clear.
Classification
While many drugs clearly fall into the category of either stimulant, depressant, or hallucinogen, cannabis exhibits a mix of all properties, perhaps leaning the most towards hallucinogen or psychedelic properties, though with other effects quite pronounced as well. Though THC is typically considered the primary active component of the cannabis plant, various scientific studies have suggested that certain other cannabinoids like CBD may also play a significant role in its psychoactive effects.
Medical Use
Cannabis used medically does have several well-documented beneficial effects. Among these are: the amelioration of nausea and vomiting, stimulation of hunger in chemotherapy and AIDS patients, lowered intraocular eye pressure (shown to be effective for treating glaucoma), as well as general analgesic effects (pain reliever).
Less confirmed individual studies also have been conducted indicating cannabis to be beneficial to a gamut of conditions running from multiple sclerosis to depression. Synthesized cannabinoids are also sold as prescription drugs, including Marinol (dronabinol in the United States and Germany) and Cesamet (nabilone in Canada, Mexico, The United States and The United Kingdom).
Currently, the U.S. Food and Drug Administration (FDA) has not approved smoked marijuana for any condition or disease in the United States, largely because good quality scientific evidence for its use from U.S. studies is lacking; however, a major barrier to acquiring the necessary evidence is the lack of federal funding for this kind of research. Regardless, thirteen states have legalized cannabis for medical use. Canada, Spain, The Netherlan ds, and Austria have also legalized cannabis for medicinal use.
Less confirmed individual studies also have been conducted indicating cannabis to be beneficial to a gamut of conditions running from multiple sclerosis to depression. Synthesized cannabinoids are also sold as prescription drugs, including Marinol (dronabinol in the United States and Germany) and Cesamet (nabilone in Canada, Mexico, The United States and The United Kingdom).
Currently, the U.S. Food and Drug Administration (FDA) has not approved smoked marijuana for any condition or disease in the United States, largely because good quality scientific evidence for its use from U.S. studies is lacking; however, a major barrier to acquiring the necessary evidence is the lack of federal funding for this kind of research. Regardless, thirteen states have legalized cannabis for medical use. Canada, Spain, The Netherlan ds, and Austria have also legalized cannabis for medicinal use.
Long-term Effects
The smoking of cannabis is the most harmful method of consumption, as the inhalation of smoke from organic materials can cause various health problems.
By comparison, studies on the vaporization of cannabis found that subjects were "only 40% as likely to report respiratory symptoms as users who do not vaporize, even when age, sex, cigarette use, and amount of cannabis consumed are controlled." Another study found vaporizers to be "a safe and effective cannabinoid delivery system."
While a study in New Zealand of 79 lung-cancer patients suggested daily cannabis smokers have a 5.7 times higher risk of lung cancer than non-users, another study of 2252 people in Los Angeles failed to find a correlation between the smoking of cannabis and lung, head or neck cancers. Some studies have also found that moderate cannabis use may protect against head and neck cancers, as well as lung cancer. Some studies have shown that cannabidiol may also be useful in treating breast cancer. These effects have been attributed to the well documented anti-tumoral properties of cannabinoids, specifically tetrahydrocannabinol (THC) and cannabidiol. Cannabis use has been assessed by several studies to be correlated with the development of anxiety, psychosis, and depression. Indeed, a 2007 meta-analysis estimated that cannabis use is statistically associated, in a dose-dependent manner, to an increased risk in the development of psychotic disorders, including schizophrenia. No causal mechanism has been proven, however, and the meaning of the correlation and its direction is a subject of debate that has not been resolved in the scientific community. 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, while other studies assess the opposite direction of the causality, or hold cannabis to only form parts of a "causal constellation", while not inflicting mental health problems that would not have occurred in the absence of the cannabis use.
Though cannabis use has at times been associated with stroke, there is no firmly established link, and potential mechanisms are unknown. Similarly, there is no established relationship between cannabis use and heart disease, including exacerbation of cases of existing heart disease. Though some fMRI studies have shown changes in neurological function in long term heavy cannabis users, no long term behavioral effects after abstinence have been linked to these changes.
By comparison, studies on the vaporization of cannabis found that subjects were "only 40% as likely to report respiratory symptoms as users who do not vaporize, even when age, sex, cigarette use, and amount of cannabis consumed are controlled." Another study found vaporizers to be "a safe and effective cannabinoid delivery system."
While a study in New Zealand of 79 lung-cancer patients suggested daily cannabis smokers have a 5.7 times higher risk of lung cancer than non-users, another study of 2252 people in Los Angeles failed to find a correlation between the smoking of cannabis and lung, head or neck cancers. Some studies have also found that moderate cannabis use may protect against head and neck cancers, as well as lung cancer. Some studies have shown that cannabidiol may also be useful in treating breast cancer. These effects have been attributed to the well documented anti-tumoral properties of cannabinoids, specifically tetrahydrocannabinol (THC) and cannabidiol. Cannabis use has been assessed by several studies to be correlated with the development of anxiety, psychosis, and depression. Indeed, a 2007 meta-analysis estimated that cannabis use is statistically associated, in a dose-dependent manner, to an increased risk in the development of psychotic disorders, including schizophrenia. No causal mechanism has been proven, however, and the meaning of the correlation and its direction is a subject of debate that has not been resolved in the scientific community. 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, while other studies assess the opposite direction of the causality, or hold cannabis to only form parts of a "causal constellation", while not inflicting mental health problems that would not have occurred in the absence of the cannabis use.
Though cannabis use has at times been associated with stroke, there is no firmly established link, and potential mechanisms are unknown. Similarly, there is no established relationship between cannabis use and heart disease, including exacerbation of cases of existing heart disease. Though some fMRI studies have shown changes in neurological function in long term heavy cannabis users, no long term behavioral effects after abstinence have been linked to these changes.
Adulterants
Adulterants in cannabis are less common than in other drugs of abuse. Chalk (in the Netherlands) and glass particles (in the UK) have been used at times to make cannabis appear to be higher quality. Increasing the weight of hashish products in Germany with lead caused lead intoxication in at least 29 users.In the Netherlands two chemical analogs of Sildenafil (Viagra) were found in adulterated marijuana.
