Marijuana has been used for millennia in foods or smoked to provide a "high" or sensation of easiness, relaxation, and detachment from reality.  It is derived from the genus Cannabis and the species sativa or indicus or one of the hybrids or genetically modified strains.  The leaves provide the material for smoking but the stems may also contain some psychoactive ingredient.  The most powerful component is 9-delta tetrahydrocannabinol (THC) but it also contains cannabinol, cannabidiol, hydroxy-THC, and over 100 other chemicals, some of which the effects on the body remain unknown. Marijuana (also known as MJ, Mary Jane, bud, dank, doobage, dope, ganja, grass, green, hemp, herb, pot, trees, twig, whacky tobaccy, weed) is smoked in rolled cigarettes, smoked in a water pipe (removes some of the toxins and cools the smoke to make the experience more pleasurable), or eaten in brownies or other baked foods.  

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Marijuana in the US exists in a legal no-mans land in 2018, being under federal law a drug that is prohibited from use for any purpose as it is considered to be highly addictive or has no medical use.  However more than half the states have passed their own laws for medical and/or recreational marijuana (including Florida), encouraged by the complicity of multiple US presidents (Bush, Obama, Trump) in the willful non-enforcement of the federal law (in violation of US Supreme Court rulings) in places where there is a state law allowing use.  California legislators crafted a "medical marijuana" bill that permitted a physician to certify a patient for usage for virtually anything, and subsequently 95% of those certified to use marijuana have absolutely nothing wrong with them at all- they and the California legislature used the medical profession as a shill in order to obtain recreational marijuana for their entire population.  In Florida the situation is even more muddled due to the Compassionate Use Law for Low THC Cannabidiol passed in 2014 and implemented in 2015.  Then in 2016, a Florida Constitutional amendment was passed to allow medical use of marijuana, with no limit on THC, and with no limits on how the drug may be taken.  Subsequently, the Florida state legislature refused to craft a statute to put the constitutional amendment in force and dovetail the existing low THC law until a special session was called.  Then the Florida legislature decided to make smoking of medical marijuana illegal due to concerns about the health effects of smoking anything, and due to reports of lip and oral cancer incidence being much higher in marijuana smokers compared to non-smokers.  Currently CBD oil is available in marijuana dispensaries but is also widely illegally available on the internet and in stores that sell other psychoactive drugs such as kratom.  Marijuana is sold in dispensaries in the form of edibles or vaping material and may contain high doses of THC.  Physicians may prescribe medical marijuana for several medical purposes including HIV+, AIDS, Parkinson's disease, glaucoma, seizure disorders,  Amyotrophic Lateral Sclerosis, Crohn's disease, post traumatic stress disorder, cancer, other similar conditions, and chronic intractable non-malignant pain due to one of the other diagnoses in this list.  Some physicians illegally are prescribing the drug for indications that are not on the list such as chronic non-malignant pain from any reason or "anxiety".  These physicians may lose their license to practice medicine in Florida leaving their patients without an immediate source of marijuana.    

 

As far as proven medical uses for marijuana, there are very few supportive studies and are limited to the treatment of AIDs symptoms including HIV neuropathy, cachexia (severe and dangerous weight loss without appetite), and glaucoma.  Most other uses, including using marijuana for pain, are speculative or have been disproven.  Marijuana may help some (but not all) types of neuropathic pain (pain derived from nerves).  It works very poorly in mechanical pain, not giving significant pain relief but causing sedation and a disconnection from reality so the person doesn't care as much about the pain (much like alcohol). 

 

But even without the laws allowing for medical use, marijuana is the most commonly used illicit drug by far in the US, with 50% of the population having tried the drug. The drug has steadily increased in 9-delta tetrahydrocannabinol (THC), the major psychoactive component, since the 1970s when the average THC content was 1.4%.  In the early 2000s, the average content was 7%.  The latest Colorado strains have THC content of 30%. Some concentrates have a THC content of 80%.  Most users of cannabis have no idea what the content of the marijuana is that they are using nor whether it was laced with other drugs or chemicals. Enforcement of marijuana possession laws becomes muddled in states with legalized medical or recreational marijuana as officers become less and less likely to prosecute with these a patchwork of confusing laws and state Constitutional amendments on the books. But enforcement of the federal ban on marijuana is still a possibility with the US Attorney General Jeff Sessions in January 2018 declaring federal prosecutors should consider prosecuting the use of marijuana in the US as it remains an illegal drug.  Congress for decades has failed to consider legalization of the drug for any purpose, medical or recreational, and the current Congress as of early 2018 is no different.

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Properties of Marijuana

 

Addiction and Dependency

The question of whether addiction occurs with marijuana is problematic since some of the key features associated with addiction are missing in most using marijuana such as tolerance and significant withdrawal symptoms. 

However 9% of those who try marijuana will become dependent on using the drug long term.  Dependency according to the DSM-V is "Continued use of marijuana despite clinically significant impairment". However dependency is not completely equivalent to addiction since it is possible to be dependent but not addicted to marijuana. Up to 30% will develop some type of marijuana use disorder (JAMA Psychiatry. 2015;72(12):1235-1242). There are four genes that may explain a maximum of 20% of those using marijuana for a lifetime, however there is a much stronger correlation to cigarette smoking and marijuana use (Transl Psychiatry. 2016 Mar 29;6:e769). Addiction to marijuana, for the most part is not a significant issue whereas dependency is.  

Cannabis dependency is often due to prolonged and increasing use of the drug. Increasing the strength of the cannabis taken and an increasing use of more effective methods of delivery often increase the progression of cannabis dependency. Dependence on cannabis is more common among heavy users, and is far greater for those using the more concentrated strains (skunk, 15% THC) compared to lower concentrated strains (grass, 9% THC) as studied in Psychol Med. 2015 Nov; 45(15): 3181–3189. Marijuana use can lead to increased tolerance only in some patients and, in some users, very mild withdrawal symptoms when trying to stop. Prolonged marijuana use produces both pharmacokinetic changes (how the drug is absorbed, distributed, metabolized, and excreted) and pharmacodynamic changes (how the drug interacts with target cells) to the body. These changes require the user to consume higher doses of the drug to achieve a common desirable effect (known as a higher tolerance), reinforcing the body's metabolic systems for eliminating the drug more efficiently and further downregulating cannabinoid receptors in the brain. These effects compound themselves in that the chronic user must consume more frequently to overcome the accelerated clearance, and higher doses to overcome the blunted response to receptor activation. Cannabis users have shown decreased reactivity to dopamine, suggesting a possible link to a dampening of the reward system of the brain and an increase in negative emotionality and severity of dependence.

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Acute Effects  Verbal learning and memory and attention are most consistently impaired by acute and chronic exposure to cannabis. Psychomotor function is most affected during acute intoxication (Biol Psychiatry. 2016 Apr 1;79(7):557-67.)  The desirable effects (the "high") of marijuana include:

• Feelings of intoxication and detachment

• Relaxation

• Intensified senses

• Laughter, talkativeness

• Hunger (many who use marijuana eat more)

 

Acute Adverse effects

It may cause an elevation in blood pressure that in those with cardiac conditions may lead to heart attacks. (Rev Med Chil. 2016 Jan;144(1):39-46.) however those smoking marijuana having heart attacks are much younger than the general population with heart attacks. Acute adverse effects also include hyperemesis syndrome (intractable nausea and vomiting), impaired coordination and performance, anxiety, suicidal ideations/tendencies, and psychotic symptoms. Acute cannabis consumption is also associated with an increased risk of motor vehicle crashes, especially fatal collisions. Higher concentrations of marijuana have a significant increase in the amount of psychosis from the drug compared to lower dosages (Psychol Med. 2015 Nov; 45(15): 3181–3189).

 

Chronic Usage  One of the most controversial and debated aspects of long term usage of marijuana is on the effect on cognitive function and intelligence.  However longitudinal (long term) studies following the same subjects found that there are more disconnections in the brain, a decrease in cognitive function, and in IQ  (Cereb Cortex. 2016 Feb 23).  Several other studies suggest the same outcome.  There is some evidence for persistent psychomotor function impairment in chronic users and after cessation of use. Impaired verbal memory, attention, and some executive functions may persist after prolonged abstinence. (Biol Psychiatry. 2016 Apr 1;79(7):557-67.) Evidence indicates that frequent and prolonged use of cannabis can be detrimental to both mental and physical health. Chronic effects of cannabis use include mood disorders, exacerbation of psychotic disorders in vulnerable people,cannabis use disorders, withdrawal syndrome, neurocognitive impairments, cardiovascular and respiratory (COPD, bronchitis) and other diseases. It also results in sexual dysfunction, lower birthweight children, and lower IQ/cognitive function in offspring.

 

Tolerance  Tolerance does not significantly develop to marijuana in most people.  Therefore the impairments in cognitive skills and physical skills (such as driving) are impaired significantly regardless of the length of time of steady use of the drug.  The importance of this fact is that even those who have used the drugs for many years will have impairment in decisionmaking and manual skills with each subsequent use of marijuana. (Sci Rep. 2016 May 26;6:26843) 

 

Withdrawal  Withdrawal symptoms from marijuana tend to be very mild with only 40% experiencing any significant withdrawal symptoms that include 

• Being irritable

• Feeling anxious or worried

• Feeling depressed

• Being restless

• Having trouble sleeping at night and feeling tired during the day

• Having low appetite or losing weight

• Various forms of physical discomfort that peak within the first week after quitting and last up to 2 weeks

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Hyperemesis Syndrome  Increasing numbers of smokers of marijuana nationwide, especially heavy or continuous smokers, are reporting uncontrollable retching and vomiting when marijuana is used excessively.  Most patients end up in the emergency department, and frequently the usual drugs available to treat excessive vomiting are ineffective, and the patient must continue to vomit for hours until the drug levels finally decrease in the blood. Some of these patients are hospitalized due to this syndrome.