Cannabis is a plant that can be smoked, vaped, eaten, ingested, or absorbed in other forms such as balms and tinctures.
After alcohol, cannabis is the most commonly used psychotropic substance in the United States.
Cannabis is Schedule I drug under the federal Controlled Substances Act of 1970. Cannabis use is illegal for any reason under federal law. However, some states have legislated exemptions for medical and recreational use.
Pharmacology is a branch of science that deals with the study of drugs and their actions on living systems - that is, the study of how drugs work in the body.
Cannabis acts by binding to endocannabinoid receptors all over the body. The endocannabinoid system is poorly understood, but may be involved in development, memory, mood, immune function, metabolism, pain, and much more (1).
Effects of acute cannabis exposure vary. Most people report euphoria, mirthfulness, dry eyes and mouth, mild paranoia, memory disturbances, and increased appetite. Less frequently, people experience dysphoria, hallucinations, or panic.
Cannabis increases the heart rate, but does not have any effect on breathing.
Prolonged exposure does not result in physical dependence.
Long term health effects are poorly understood and conflicting.
If smoked, respiratory and cardiovascular symptoms may occur.
There is emerging evidence of rare complications with the use of cannabis oils, or “dabs”. Healthy young men have presented with elevated troponin, seizures, and psychosis. It is unclear whether these effects are caused by contamination from the manufacturing process, elevated ratios of tetrahydrocannabinol (THC) to cannabidiol (CBD), or something else (2).
Is marijuana bad for your brain?
"In 1970, marijuana was classified as a schedule 1 drug in the United States: the strictest designation possible, meaning it was completely illegal and had no recognized medical uses. Today, marijuana’s therapeutic benefits are widely acknowledged, but a growing recognition for its medical value doesn’t answer the question: is recreational marijuana use bad for your brain? Anees Bahji investigates."
There are no treatment medications for supporting cessation of cannabis use.
If cannabis is being used to self-medicate for conditions like nausea, anxiety, or pain other medications may be useful in treatment.
Individual or group therapy may be help some people reach their goals for changing their patterns of use.
Maternal effects are poorly understood.
Interpretation of data is complicated because cannabis users who are identified by healthcare providers and law enforcement authorities are more likely to have negative social determinants of health such as polysubstance use, poverty, and history of trauma than their unidentified counterparts (3).
In some studies, pregnant people report decreased nausea with cannabis use (4, 5), and there are also paradoxical findings of increased incidence and severity of nausea with cannabis use (6, 7).
There are no good data separating neonatal effects of pre- and postnatal exposure.
The human brain contains endocannabinoid receptors by 14 weeks gestation, which could suggest that the endocannabinoid system plays a role in early brain development (3).
There is some evidence of temporarily decreased developmental scores and possible mood disturbances in exposed offspring (8), and there is also evidence of no effect (9), and of slightly increased developmental scores (10-12).
There is some evidence of lower birth weights associated with heavier cannabis use, but data are unclear about whether this risk is clinically significant. There is no evidence of congenital anomalies, cancer, preterm delivery, or feeding problems (3). The effects, if any, appear to be mild, and are poorly understood.
Cannabis metabolites are present in the human milk of people who consume it (13, 14).
Transfer into human milk is estimated to be 0.8-1% of maternal dose (15, 16).
Infant bioavailability via the gastrointestinal tract is unknown, and it is likely that absorption is not complete.
There is very little data on the effects of exposure to cannabis via breast milk, and results are inconclusive (12, 17).
Current recommendations are to reduce or eliminate use during the lactation period (3, 18, 19).
However, in the case of continued medical or recreational use, experts agree that the proven benefits of human milk are likely to outweigh the risk of cannabis exposure, and there is no justification for withholding lactation support (15, 20). As one researcher stated: “Least preferable is continuation of marijuana use in conjunction with bottle-feeding” (15).
It is impossible to overdose on cannabis, since it does not depress respiration (breathing).
It may aggravate existing heart conditions or mental health conditions, but cannabis use can be a contributing factor - instead of the direct cause - of death.
Cannabis as a Case Study in Safe Drug Supply
Legalization and decriminalization of cannabis has resulted in decreased risks for people who use it.
Apart from the overwhelming health benefits of avoiding criminal and carceral systems, there are other obvious health benefits.
A safe cannabis supply empowers people to take control of their use and make safer choices.
People who have access to regulated, safe supplies of their drug of choice:
can make informed choices about what they use
can choose products with safer routes of administration than smoking
know what they are using because products are labeled and their cannabinoid profile, including the percentages of THC and CBD, inactive ingredients, and - in the case of edibles - serving size are listed on products
can use less product and still get the desired effect
can purchase products in a safe environment, free of the predation and harassment that many women and other vulnerable people face when buying illicit substances.
Learn more about how safe drug supplies reduce the danger of overdose and poisoning.
Cannabis withdrawal is associated with increased irritability, anxiety, sleep disturbances, appetite disturbances, depression, and physical symptoms such as sweating, headache, stomach pain, and fever. The quality of evidence is poor, and some patients may be reporting underlying conditions which reemerge after self-medication with cannabis is withdrawn (21).
1. Jutras-Aswad, D., DiNieri, J. A., Harkany, T., & Hurd, Y. L. (2009). Neurobiological consequences of maternal cannabis on human fetal development and its neuropsychiatric outcome. European archives of psychiatry and clinical neuroscience, 259(7), 395–412.
2. Alzghari, S. K., Fung, V., Rickner, S. S., Chacko, L., & Fleming, S. W. (2017). To Dab or Not to Dab: Rising Concerns Regarding the Toxicity of Cannabis Concentrates. Cureus, 9(9), e1676.
3. American College of Obstetricians and Gynecologists Committee on Obstetric Practice (2015). Committee Opinion No. 637: Marijuana Use During Pregnancy and Lactation. Obstetrics and gynecology, 126(1), 234–238.
4. Hayes, J. S., Dreher, M. C., & Nugent, J. K. (1988). Newborn outcomes with maternal marihuana use in Jamaican women. Pediatric nursing, 14(2), 107–110.
5. Westfall, R. E., Janssen, P. A., Lucas, P., & Capler, R. (2006). Survey of medicinal cannabis use among childbearing women: patterns of its use in pregnancy and retroactive self-assessment of its efficacy against 'morning sickness'. Complementary therapies in clinical practice, 12(1), 27–33.
6. Roberson, E. K., Patrick, W. K., & Hurwitz, E. L. (2014). Marijuana use and maternal experiences of severe nausea during pregnancy in Hawai'i. Hawai'i journal of medicine & public health : a journal of Asia Pacific Medicine & Public Health, 73(9), 283–287.
7. Alaniz, V. I., Liss, J., Metz, T. D., & Stickrath, E. (2015). Cannabinoid hyperemesis syndrome: a cause of refractory nausea and vomiting in pregnancy. Obstetrics and gynecology, 125(6), 1484–1486.
8. Fried P. A. (1995). Prenatal exposure to marihuana and tobacco during infancy, early and middle childhood: effects and an attempt at synthesis. Archives of toxicology. Supplement. = Archiv fur Toxikologie. Supplement, 17, 233–260.
9. Day, N. L., Richardson, G. A., Geva, D., & Robles, N. (1994). Alcohol, marijuana, and tobacco: effects of prenatal exposure on offspring growth and morphology at age six. Alcoholism, clinical and experimental research, 18(4), 786–794.
10. Dreher, M. C., Nugent, K., & Hudgins, R. (1994). Prenatal marijuana exposure and neonatal outcomes in Jamaica: an ethnographic study. Pediatrics, 93(2), 254–260.
11. Fried, P. A., & Watkinson, B. (2000). Visuoperceptual functioning differs in 9- to 12-year olds prenatally exposed to cigarettes and marihuana. Neurotoxicology and teratology, 22(1), 11–20.
12. Astley, S. J., & Little, R. E. (1990). Maternal marijuana use during lactation and infant development at one year. Neurotoxicology and teratology, 12(2), 161–168.
13. Perez-Reyes, M., & Wall, M. E. (1982). Presence of delta9-tetrahydrocannabinol in human milk. The New England journal of medicine, 307(13), 819–820.
14. Bertrand, K. A., Hanan, N. J., Honerkamp-Smith, G., Best, B. M., & Chambers, C. D. (2018). Marijuana Use by Breastfeeding Mothers and Cannabinoid Concentrations in Breast Milk. Pediatrics, 142(3), e20181076.
15. Hill, M., & Reed, K. (2013). Pregnancy, breast-feeding, and marijuana: a review article. Obstetrical & gynecological survey, 68(10), 710–718.
16. D'Apolito K. (2013). Breastfeeding and substance abuse. Clinical obstetrics and gynecology, 56(1), 202–211.
17. Tennes, K., Avitable, N., Blackard, C., Boyles, C., Hassoun, B., Holmes, L., & Kreye, M. (1985). Marijuana: prenatal and postnatal exposure in the human. NIDA research monograph, 59, 48–60.
18. Section on Breastfeeding (2012). Breastfeeding and the use of human milk. Pediatrics, 129(3), e827–e841.
19. Reece-Stremtan, S., & Marinelli, K. A. (2015). ABM clinical protocol #21: guidelines for breastfeeding and substance use or substance use disorder, revised 2015. Breastfeeding medicine : the official journal of the Academy of Breastfeeding Medicine, 10(3), 135–141.
20. Metz, T. D., & Stickrath, E. H. (2015). Marijuana use in pregnancy and lactation: a review of the evidence. American journal of obstetrics and gynecology, 213(6), 761–778.
21. Gorelick, D. A., Levin, K. H., Copersino, M. L., Heishman, S. J., Liu, F., Boggs, D. L., & Kelly, D. L. (2012). Diagnostic criteria for cannabis withdrawal syndrome. Drug and alcohol dependence, 123(1-3), 141–147.