medical cannabis medical cannabis medical cannabis, or medical marijuana (mmj), is cannabis and cannabinoids that are prescribed by physicians for their patients. the use of cannabis as medicine has not been rigorously tested due to production and governmental restrictions, resulting in limited clinical research to define the safety and efficacy of using cannabis to treat diseases. part of a series oncannabis artsculture 420 books magu (deity) names religion judaism latter-day saints sikhism smoke-in spiritual use sports stoner film stoner rock terms chemistry cannabinoid receptors cannabinoid receptor type 1 cannabinoid receptor type 2 cannabinoids 2-ag 2-age, noladin ether aea cbc cbl cbd cbdv cbg cbn cbv nada thc thcv virodhamine synthetic cannabinoids am-2201 cp-55940 dimethylheptylpyran hu-210 hu-331 jwh-018 jwh-073 jwh-133 levonantradol sr144528 win 55,212-2 consumption drinks edibles smoking tea vaping adult lifetime cannabis use by country annual cannabis use by country economics coffeeshop cultivation shop social club grow house grow shop head shop marijuana vending machine effects dependence driving drug testing effects of legalized cannabis gateway drug theory long term effects medicine memory pregnancy psychosis time perception forms bhang blunt charas flower essential oil hash oil hashish hemp hemp oil joint kief roach synthetic cannabis thai stick tincture law cannabis rights legality of cannabis timeline of cannabis law legality of cannabis in us legal history of cannabis in us us (medical non-medical timeline) cannabis act of canada legal history of cannabis in canada drug policy of california drug policy of the netherlands drug policy of portugal variants autoflowering cannabis genus cannabis species cannabis sativa cannabis indica cannabis ruderalis strains acapulco gold blue dream charlotte's web kush malawi gold sour diesel related drug culture illegal drug trade psychedelia cannabis portal medicine portal agriculture portal preliminary evidence has indicated that cannabis might reduce nausea and vomiting during chemotherapy and reduce chronic pain and muscle spasms. regarding non-inhaled cannabis or cannabinoids, a 2021 review found that it provided little relief against chronic pain and sleep disturbance, and caused several transient adverse effects, such as cognitive impairment, nausea, and drowsiness. short-term use increases the risk of minor and major adverse effects. common side effects include dizziness, feeling tired, vomiting, and hallucinations. long-term effects of cannabis are not clear. concerns include memory and cognition problems, risk of addiction, schizophrenia in young people, and the risk of children taking it by accident. many cultures have used cannabis for therapeutic purposes for thousands of years. some american medical organizations have requested removal of cannabis from the list of schedule i controlled substances maintained by the united states federal government, followed by regulatory and scientific review. others oppose its legalization, such as the american academy of pediatrics. medical cannabis can be administered through various methods, including capsules, lozenges, tinctures, dermal patches, oral or dermal sprays, cannabis edibles, and vaporizing or smoking dried buds. synthetic cannabinoids are available for prescription use in some countries, such as dronabinol and nabilone. countries that allow the medical use of whole-plant cannabis include argentina, australia, canada, chile, colombia, germany, greece, israel, italy, the netherlands, peru, poland, portugal, spain, and uruguay. in the united states, 38 states and the district of columbia have legalized cannabis for medical purposes, beginning with the passage of california's proposition 215 in 1996. although cannabis remains prohibited for any use at the federal level, the rohrabacher–farr amendment was enacted in december 2014, limiting the ability of federal law to be enforced in states where medical cannabis has been legalized. classification the national institute on drug abuse defines medical cannabis as "using the whole, unprocessed marijuana plant or its basic extracts to treat symptoms of illness and other conditions". a cannabis plant includes more than 400 different chemicals, of which about 70 are cannabinoids. in comparison, typical government-approved medications contain only one or two chemicals. the number of active chemicals in cannabis is one reason why treatment with cannabis is difficult to classify and study. a 2014 review stated that the variations in ratio of cbd-to-thc in botanical and pharmaceutical preparations determines the therapeutic vs psychoactive effects (cbd attenuates thc's psychoactive effects) of cannabis products. medical uses cannabis as illustrated in köhler's book of medicinal plants, 1897 overall, research into the health effects of medical cannabis has been of low quality and it is not clear whether it is a useful treatment for any condition, or whether harms outweigh any benefit. there is no consistent evidence that it helps with chronic pain and muscle spasms. low quality evidence suggests its use for reducing nausea during chemotherapy, improving appetite in hiv/aids, improving sleep, and improving tics in tourette syndrome. when usual treatments are ineffective, cannabinoids have also been recommended for anorexia, arthritis, glaucoma, and migraine. it is unclear whether american states might be able to mitigate the adverse effects of the opioid epidemic by prescribing medical cannabis as an alternative pain management drug. cannabis should not be used in pregnancy. nausea and vomiting medical cannabis is somewhat effective in chemotherapy-induced nausea and vomiting (cinv) and may be a reasonable option in those who do not improve following preferential treatment. comparative studies have found cannabinoids to be more effective than some conventional antiemetics such as prochlorperazine, promethazine, and metoclopramide in controlling cinv, but these are used less frequently because of side effects including dizziness, dysphoria, and hallucinations. long-term cannabis use may cause nausea and vomiting, a condition known as cannabinoid hyperemesis syndrome (chs). a 2016 cochrane review said that cannabinoids were "probably effective" in treating chemotherapy-induced nausea in children, but with a high side-effect profile (mainly drowsiness, dizziness, altered moods, and increased appetite). less common side effects were "ocular problems, orthostatic hypotension, muscle twitching, pruritus, vagueness, hallucinations, lightheadedness and dry mouth". hiv/aids evidence is lacking for both efficacy and safety of cannabis and cannabinoids in treating patients with hiv/aids or for anorexia associated with aids. as of 2013, current studies suffer from the effects of bias, small sample size, and lack of long-term data. pain a 2021 review found little effect of using non-inhaled cannabis to relieve chronic pain. according to a 2019 systematic review, there have been inconsistent results of using cannabis for neuropathic pain, spasms associated with multiple sclerosis and pain from rheumatic disorders, but was not effective treating chronic cancer pain. the authors state that additional randomized controlled trials of different cannabis products are necessary to make conclusive recommendations. when cannabis is inhaled to relieve pain, blood levels of cannabinoids rise faster than when oral products are used, peaking within three minutes and attaining an analgesic effect in seven minutes. a 2011 review considered cannabis to be generally safe, and it appears safer than opioids in palliative care. a 2022 review concluded the pain relief experienced after using medical cannabis is due to the placebo effect, especially given widespread media attention that sets the expectation for pain relief. neurological conditions cannabis' efficacy is not clear in treating neurological problems, including multiple sclerosis (ms) and movement problems. evidence also suggests that oral cannabis extract is effective for reducing patient-centered measures of spasticity. a trial of cannabis is deemed to be a reasonable option if other treatments have not been effective. its use for ms is approved in ten countries. a 2012 review found no problems with tolerance, abuse, or addiction. in the united states, cannabidiol, one of the cannabinoids found in the marijuana plant, has been approved for treating two severe forms of epilepsy, lennox-gastaut syndrome and dravet syndrome. mental disorders further information: posttraumatic stress disorder § cannabinoids a 2019 systematic review found that there is a lack of evidence that cannabinoids are effective in treating depressive or anxiety disorders, attention-deficit hyperactivity disorder (adhd), tourette syndrome, post-traumatic stress disorder, or psychosis. adverse effects american medical hashish medical use there is insufficient data to draw strong conclusions about the safety of medical cannabis. typically, adverse effects of medical cannabis use are not serious; they include tiredness, dizziness, increased appetite, and cardiovascular and psychoactive effects. other effects can include impaired short-term memory; impaired motor coordination; altered judgment; and paranoia or psychosis at high doses. tolerance to these effects develops over a period of days or weeks. the amount of cannabis normally used for medicinal purposes is not believed to cause any permanent cognitive impairment in adults, though long-term treatment in adolescents should be weighed carefully as they are more susceptible to these impairments. withdrawal symptoms are rarely a problem with controlled medical administration of cannabinoids. the ability to drive vehicles or to operate machinery may be impaired until a tolerance is developed. although supporters of medical cannabis say that it is safe, further research is required to assess the long-term safety of its use. cognitive effects further information: long-term effects of cannabis recreational use of cannabis is associated with cognitive deficits, especially for those who begin to use cannabis in adolescence. as of 2021 there is a lack of research into long-term cognitive effects of medical use of cannabis, but one 12-month observational study reported that "mc patients demonstrated significant improvements on measures of executive function and clinical state over the course of 12 months". impact on psychosis exposure to thc can cause acute transient psychotic symptoms in healthy individuals and people with schizophrenia. a 2007 meta analysis concluded that cannabis use reduced the average age of onset of psychosis by 2.7 years relative to non-cannabis use. a 2005 meta analysis concluded that adolescent use of cannabis increases the risk of psychosis, and that the risk is dose-related. a 2004 literature review on the subject concluded that cannabis use is associated with a two-fold increase in the risk of psychosis, but that cannabis use is "neither necessary nor sufficient" to cause psychosis. a french review from 2009 came to a conclusion that cannabis use, particularly that before age 15, was a factor in the development of schizophrenic disorders. pharmacology the genus cannabis contains two species which produce useful amounts of psychoactive cannabinoids: cannabis indica and cannabis sativa, which are listed as schedule i medicinal plants in the us; a third species, cannabis ruderalis, has few psychogenic properties. cannabis contains more than 460 compounds; at least 80 of these are cannabinoids – chemical compounds that interact with cannabinoid receptors in the brain. as of 2012, more than 20 cannabinoids were being studied by the u.s. fda. the most psychoactive cannabinoid found in the cannabis plant is tetrahydrocannabinol (or delta-9-tetrahydrocannabinol, commonly known as thc). other cannabinoids include delta-8-tetrahydrocannabinol, cannabidiol (cbd), cannabinol (cbn), cannabicyclol (cbl), cannabichromene (cbc) and cannabigerol (cbg); they have less psychotropic effects than thc, but may play a role in the overall effect of cannabis. the most studied are thc, cbd and cbn. cb1 and cb2 are the primary cannabinoid receptors responsible for several of the effects of cannabinoids, although other receptors may play a role as well. both belong to a group of receptors called g protein-coupled receptors (gpcrs). cb1 receptors are found in very high levels in the brain and are thought to be responsible for psychoactive effects. cb2 receptors are found peripherally throughout the body and are thought to modulate pain and inflammation. absorption cannabinoid absorption is dependent on its route of administration. inhaled and vaporized thc have similar absorption profiles to smoked thc, with a bioavailability ranging from 10 to 35%. oral administration has the lowest bioavailability of approximately 6%, variable absorption depending on the vehicle used, and the longest time to peak plasma levels (2 to 6 hours) compared to smoked or vaporized thc. similar to thc, cbd has poor oral bioavailability, approximately 6%. the low bioavailability is largely attributed to significant first-pass metabolism in the liver and erratic absorption from the gastrointestinal tract. however, oral administration of cbd has a faster time to peak concentrations (2 hours) than thc. due to the poor bioavailability of oral preparations, alternative routes of administration have been studied, including sublingual and rectal. these alternative formulations maximize bioavailability and reduce first-pass metabolism. sublingual administration in rabbits yielded bioavailability of 16% and time to peak concentration of 4 hours. rectal administration in monkeys doubled bioavailability to 13.5% and achieved peak blood concentrations within 1 to 8 hours after administration. distribution like cannabinoid absorption, distribution is also dependent on route of administration. smoking and inhalation of vaporized cannabis have better absorption than do other routes of administration, and therefore also have more predictable distribution. thc is highly protein bound once absorbed, with