We believe it is critically important to read and understand the research about marijuana in order to formulate informed opinions, decisions and policies on this issue.

Contrary to popular opinion, it does not need to be rescheduled to be researched. There are thousands of studies on marijuana already published. Here are a some highlighted ones that we believe are important.

*For optimal table functionality, please utilize on a laptop or desktop computer.

Marijuana Research Studies

TitleTopic(s)Key findingPublicationYearLink
Potency trends of delta9-THC and other cannabinoids in confiscated marijuana from 1980-1997.PotencyMarijuana potency and concentration of THC has increased substantially in recent decades.Journal of Forensic Sciences2000
Adolescent Cannabis Exposure Alters Opiate Intake and Opioid Limbic Neuronal Populations in Adult RatsYouth marijuana use, opioid useAdolescent marijuana exposure may increase the risk for future opioid use.Neuropsychopharmacology2007
High-potency cannabis and the risk of psychosisHigh potency, psychosisUse of high potency marijuana is associated with an increased risk of psychosis.British Journal of Psychiatry2009
Tobacco, drug use in pregnancy can double risk of stillbirthPregnancy, stillbirthMarijuana use during pregnancy is associated with a 2.3 times greater risk of stillbirth.National Institutes of Health2013
Drug Use Patterns and Continuous Enrollment in College: Results From a Longitudinal StudyMarijuana use, academic successMarijuana use is associated with a decreased likelihood of continuing enrollment in college.Journal of Studies on Alcohol and Drugs2013
Long-term effects of marijuana use on the brainMarijuana use, brain developmentChronic marijuana use was associated with lower structural connectivity in the brain.PNAS2014
Young adult sequelae of adolescent cannabis use: an integrative analysisYouth marijuana use, brain developmentAdolescent marijuana use adversely impacts brain development.Lancet Psychiatry2014
Cannabis Use: Signal of Increasing Risk of Serious Cardiovascular DisordersCardiovascular diseaseMarijuana use is associated with an increased risk of cardiovascular disease.Journal of the American Heart Association2014
Acute cannabis consumption and motor vehicle collision risk: systematic review of observational studies and meta-analysisImpaired drivingMarijuana consumption prior to driving is associated with an increased risk of motor vehicle crashes, and fatal collisions.BMJ Open2014
Probability and predictors of the cannabis gateway effect: a national study.Marijuana use, other substance use44.7% of individuals who reported lifetime marijuana use reported other drug use.The International Journal on Drug Policy2015
Marijuana Use is Associated with Worse Outcomes in Symptom Severity and Violent Behavior in Patients with PTSDMarijuana use, PTSDMarijuana use was associated with worse PTSD symptoms.Journal of Clinical Psychiatry2015
Cannabis Use in Adolescence and Young Adulthood: A Review of Findings from the Victorian Adolescent Health Cohort StudyYouth marijuana use, outcomesYouth marijuana use was significantly associated with worse academic outcomes, persistent mental health problems, heightened risk for marijuana dependence, and increased risk of other substance abuse.The Canadian Journal of Psychiatry2016
Cannabis-induced psychosis associated with high potency “wax dabs”Potency, psychosisCases of emergent psychosis were reported after use of concentrated THC extract.Schizophrenia Research2016
Is cannabis use associated with an increased risk of onset and persistence of alcohol use disorders? A three-year prospective study among adults in the United StatesMarijuana use, alcohol useMarijuana use is associated with an increased likelihood of Alcohol Use Disorder.Drug and Alcohol Dependence2016
Prenatal exposure to cannabis and maternal and child health outcomes: a systematic review and meta-analysisMarijuana use during pregnancyInfants exposed to marijuana inutero were more likely to have lower birthweight, and more likely to be placed in the neonatal ICU.BMJ Open2016
“High” Achievers? Cannabis Access and Academic PerformanceAccess, academic successThe academic performance of university students who were prohibited from buying marijuana increased.The Review of Economic Studies2017
Marijuana and acute health care contacts in ColoradoLegalization, hospitalizations, emergency department visitsLegalization in Colorado was followed by increases in hospitalizations with marijuana codes, mental illness emergency department visits with marijuana codes, and calls to the poison control center.Preventative Medicine2017
Rates and Predictors of Conversion to Schizophrenia or Bipolar Disorder Following Substance-Induced PsychosisMental health, schizophrenia, bipolar disorder47.4% of patients with cannabis-induced psychosis converted to either schizophrenia or bipolar disorder.American Journal of Psychiatry2017
Trends in perception of risk of regular marijuana use among US pregnant and nonpregnant reproductive-aged womenMarijuana use during pregnancyThe perception of risk associated with use during pregnancy has significantly decreased, in spite of the harms posed.American Journal of Obstetrician and Gynecol2017
Toxicant Formation in Dabbing: The Terpene StoryMarijuana use, dabbingDabbing, a form of vaping highly potent marijuana, may also deliver significant amounts of toxic degradation products.ACS Omega2017
Do young-adult cannabis users show amotivation? An analysis of informant reports.Marijuana use, amotivationStudy investigated an undergraduate sample and found that participants who had used marijuana 52 days or more in the past year reported higher levels of amotivation than non-using study participants or participants who had used marijuana fewer than 52 times in the past year.Translational Issues in Psychological Science2018
Framing marijuana: How U.S. newspapers frame marijuana legalization stories (1995–2014)Legalization, perceptionThe way that legalization has been framed in the media centers around public policy rather than public health.Preventative Medicine2018
The grass is not always greener: a multi-institutional pilot study of marijuana use and acute pain management following traumatic injuryMarijuana use, pain treatmentChronic marijuana use may impact pain response to injury by requiring greater use of opioid analgesia.Patient Safety in Surgery2018
Elevated Behavioral Economic Demand for Alcohol in Co-Users of Alcohol and CannabisMarijuana use, alcohol useCo-users of alcohol and marijuana tend to overvalue alcohol more than alcohol-only users, signaling dependence.Journal of Studies on Alcohol and Drugs2018
Cannabinoid Hyperemesis Syndrome: Reports of Fatal CasesLegalization, Cannabis Vomiting Syndrome (sometimes referred to as Cannabis Hyperemesis Syndrome)Profile of CVS (CHS). CVS was determined to be the cause of death in two instances.Journal of Forensic Sciences2018
Medical Marijuana Users Are More Likely to Use Prescription Drugs Medically and NonmedicallyMedical marijuana use, prescription drug useMedical marijuana users were more likely to report medical and nonmedical use of prescription drugs.Journal of Addiction Medicine2018
The emergence of cannabis agriculture frontiers as environmental threatsMarijuana cultivation, environemental harmsThe expansion of marijuana cultivation is placing a strain on the environment and may adversely impact habitat availability.IOP Science2018
Recent trends in cyclic vomiting syndrome‐associated hospitalisations with liberalisation of cannabis use in the state of ColoradoLegalization, Cannabis Vomiting Syndrome (sometimes referred to as Cannabis Hyperemesis Syndrome)Legalization in Colorado was associated with a significant increase in CVS-related hospitalizations.Internal Medicine Journal2018
Cannabis, a Significant Risk Factor for Violent Behavior in the Early Phase Psychosis. Two Patterns of Interaction of Factors Increase the Risk of Violent Behavior: Cannabis Use Disorder and Impulsivity; Cannabis Use Disorder, Lack of Insight and Treatment AdherenceMental health, psychosisMarijuana use is a risk factor among early psychosis patients.Frontiers in Psychiatry2018
Made from concentrate? A national web survey assessing dab use in the United StatesPotencyMarijuana users appear to choose dabs for experimentation rather than positive effects.Drug and Alcohol Dependence2018
Cannabis Use Disorder in Young Adults with Acute Myocardial Infarction: Trend Inpatient Study from 2010 to 2014 in the United StatesMarijuana use, heart attackChronic marijuana use worsens outcomes in patients with myocardial infarction (heart attacks) and heart attacks are on the rise among marijuana users.Cureus2018
A Population-Based Analysis of the Relationship Between Substance Use and Adolescent Cognitive DevelopmentYouth marijuana use, brain developmentYouth marijuana use adversely impacted cognitive function in users.American Journal of Psychiatry2018
Cannabis Use and Risk of Prescription Opioid Use Disorder in the United StatesMarijuana use, opioid useMarijuana use appeared to increase the risk of developing nonmedical prescription opioid use disorder.American Journal of Psychiatry2018
Onset of Regular Cannabis Use & Young Adult Insomnia: An Analysis of Shared Genetic LiabilityMarijuana use, insomniaEarly onset marijuana use (beginning at age 17 or younger) was associated with insomnia and insomnia with short sleep on weekdays.Sleep2019
Transition of Substance-Induced, Brief, and Atypical Psychoses to Schizophrenia: A Systematic Review and Meta-analysis Mental health, schizophreniaMarijuana-induced psychosis was associated with a high rate of transition to schizophrenia.Schizophrenia Bulletin2019
Association between medical cannabis laws and opioid overdose mortality has reversed over timeLegalization, opioid overdoseMarijuana legalization is not associated with a decrease in opioid-related deaths.PNAS2019
Cannabis Concentrate Use in AdolescentsYouth marijuana use, potency72% of youth (8th, 10th, 12th graders) who reported lifetime marijuana use, also reported lifetime concentrate use.Pediatrics2019
Grey Matter Volume Differences Associated with Extremely Low Levels of Cannabis Use in AdolescenceYouth marijuana use, brain developmentYouth who used marijuana showed changes in grey matter in their brains, indicating that the drug altered developmental structures in young marijuana users' brains.Neuroscience2019
The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control studyMental health, psychosis, potencyDaily use of high potency marijuana is associated with a near five-times increased odds of developing psychosis.Lancet Psychiatry2019
Association of Cannabis Use in Adolescence and Risk of Depression, Anxiety, and Suicidality in Young Adulthood: A Systematic Review and Meta-analysisYouth marijuana use, depression, suicideMarijuana use during adolescence is associated with increased risk of developing depression or suicidality in young adulthood. JAMA Psychiatry2019
Association Between Recreational Marijuana Legalization in the United States and Changes in Marijuana Use and Cannabis Use Disorder From 2008 to 2016Legalization, youth marijuana use, substance use disorderInstances of Cannabis Use Disorder (CUD) among young people aged 12-17 increased 25% after legalization.JAMA Psychiatry2019
Association Between Electronic Cigarette Use and Marijuana Use Among Adolescents and Young Adults: A Systematic Review and Meta-analysisYouth vaping, youth marijuana useYouth who used e-cigarettes were 3.5 times more likely than non-using youth to use marijuana.JAMA Pediatrics2019
Association Between Adolescent Blunt Use and the Uptake of CigarsYouth marijuana use, cigar useAdolescent blunt use is associated with an increased likelihood of future, consistent cigar use.JAMA2019
Associations of Parental Marijuana Use With Offspring Marijuana, Tobacco, and Alcohol Use and Opioid MisuseParental marijuana use, youth substance useParental marijuana use is associated with an increased risk of adolescent offspring substance misuse (tobacco, alcohol, marijuana, opioid).JAMA2019
Incidence of Pediatric Cannabis Exposure Among Children and Teenagers Aged 0 to 19 Years Before and After Medical Marijuana Legalization in MassachusettsLegalization, youth exposuresAccidental youth marijuana exposures increased in Massachusetts after medical marijuana legalization in spite of restrictions on packaging.JAMA2019
Trends in Opioid Misuse among Marijuana Users and Non-Users in the U.S. from 2007–2017Opioid misuseMarijuana use is significantly associated with prescription opioid misuse.International Journal of Environmental Research and Public Health2019
New trends in cannabis potency in USA and Europe during the last decade (2008–2017)PotencyTHC concentration in marijuana products has increased dramatically in the past ten years. The average marijuana plant was found to contain upwards of 17% THC in 2017, up from under 9% in 2008.European Archives of Psychiatry and Clinical Neuroscience2019
Active cannabis marketing and adolescent past-year cannabis useYouth marijuana use, marijuana marketingYouth who liked or followed marijuana social media accounts were five times more likely to have used marijuana in the past year. Drug and Alcohol Dependence2019
Male Marijuana Use Might Double the Risk of Partner’s MiscarriagePregnancy, miscarriageMale marijuana use is associated with an increased risk of miscarriage in pregnant partners, regardless of the woman's use habits.Boston University2019
Vaping cannabis among adolescents: prevalence and associations with tobacco use from a cross-sectional study in the USAYouth vaping, youth marijuana useYouth who vaped or used tobacco products were more likely to use or vape marijuana.BMJ Open2019
Post-Legalization Opening of Retail Cannabis Stores and Adult Cannabis Use in Washington State, 2009–2016Legalization, use habitsMarijuana use and frequent marijuana use among adults in Washington state increased after legalization. Greater use was associated with proximity to marijuana retail stores.American Journal of Public Health2019
Cannabinoid exposure in rat adolescence reprograms the initial behavioral, molecular, and epigenetic response to cocaineMarijuana use, other substance useA study on rats found that adolescent exposure to marijuana alters the initial responses to cocaine, making marijuana users more susceptible to continued cocaine use.PNAS2020
Mapping cannabis potency in medical and recreational programs in the United StatesPotency, efficacy, medical marijuanaA majority of marijuana products are advertized to have >15% THC, regardless of medical or recreational programs, which may be detrimental for medical purposes.PLoS One2020
Birth and early developmental screening outcomes associated with cannabis exposure during pregnancyPregnancy, small for gestational age birthMarijuana use during pregnancy is associated with an increased risk for small for gestational age births.Journal of Perinatology2020
Vaporized Cannabis Extracts Have Reinforcing Properties and Support Conditioned Drug-Seeking Behavior in RatsAddiction, marijuana vapingTHC-heavy marijuana vapor appeared to enhance drug-seeking behavior in rats.Journal of Neuroscience2020
Exposure to Cannabis Marketing in Social and Traditional Media and Past-Year Use Among Adolescents in States With Legal Retail CannabisYouth marijuana use, marijuana marketingAdolescent exposure to marijuana on social media is associated with recent marijuana use.Journal of Adolescent Health2020
Prevalence of Cannabis Withdrawal Symptoms Among People With Regular or Dependent Use of Cannabinoids A Systematic Review and Meta-analysisMarijuana use, dependence47% of regular or dependent marijuana users were found to have Cannabis Withdrawal Syndrome (CWS).JAMA2020
Intensity of cannabis use: Findings from three online surveysMarijuana use, consumptionStudy respondents who reported daily marijuana use consumed nearly two times the amount of marijuana per day compared with users who used less than daily. Daily users of marijuana consume marijuana more heavily than non-daily users.International Journal of Drug Policy2020
Marijuana Legalization and Youth Marijuana, Alcohol, and Cigarette Use and NormsYouth use, legalizationLegalization is linked to an increase in youth marijuana and youth alcohol use.American Journal of Preventive Medicine2020
Assessment of Incorporation of Lessons From Tobacco Control in City and County Laws Regulating Legal Marijuana in CaliforniaLegalization, regulationPolicy-makers in California failed to heed lessons from tobacco control to "reduce demand, limit harm, and prevent youth use" in the implementation of marijuana legalization in the state, "potentially creating greater risk of harm."JAMA 2020
Association Between the Use of Cannabis and Physical Violence in Youths: A Meta-Analytical InvestigationMarijuana use, violenceMarijuana use is associated with physical violence and risk of violence was higher among heavier users of marijuana.American Journal of Psychiatry2020
Psychiatric symptoms caused by cannabis constituents: a systematic review and meta-analysisMental health, psychosisThe administration of THC induces significant increases in psychotic and other psychiatric symptoms, even among those with no history of psychotic or other psychiatric disorders.Lancet Psychiatry2020
Acute effects of cannabinoids on symptoms of obsessive-compulsive disorder: A human laboratory studyMarijuana use, OCDSmoked marijuana does not appear to impact OCD symptoms.Depression and Anxiety2020
Impact of pregnancy marijuana use on birth outcomes: results from two matched population-based cohortsMarijuana use during pregnancyMarijuana exposure to newborns in utero had worse outcomes than the control group: weighing less, more likely to be pre-term or admitted to the NICU.Journal of Perinatology2020
Trajectories of cannabis use and risk for opioid misuse in a young adult urban cohortYouth marijuana use, opioid misuseAdolescent marijuana use among young Blacks in urban communities is associated with future opioid misuse.Drug and Alcohol Dependence2020
Maternal cannabis use in pregnancy and child neurodevelopmental outcomesMarijuana use during pregnancyChildren whose mothers used marijuana during pregnancy were 50% more likely to be diagnosed with autism. Prenatal marijuana exposure also may increase the risk of the child developing intellectual disabilities such as learning disorders and ADHD.Nature Medicine2020
The deleterious effects of cannabis during pregnancy on neonatal outcomesMarijuana use during pregnancyMarijuana use during pregnancy is a risk factor for worse neonatal outcomes such as low birthweight.Medical Journal of Australia2020
Association Between Self-reported Prenatal Cannabis Use and Maternal, Perinatal, and Neonatal OutcomesMarijuana use during pregnancyMarijuana use during pregnancy is significantly associated with a risk for preterm birth.JAMA2019
U.S. cannabis legalization and use of vaping and edible products among youthYouth marijuana use, legalizationLonger duration of marijuana legalization as well as dispensary density was associated with an increased likelihood of youth experimentation with marijuana vaping and consumption of edibles.Drug and Alcohol Dependence2017
Associations Between Marijuana Use Trajectories and Educational and Occupational Success in Young AdulthoodYouth marijuana use, outcomesEarly onset, persistent, and frequent marijuana use during adolescence is associated with lower educational attainment, limited occupational success, and lower income.Prevention Science2018
Cannabis Use and Risk of Psychiatric DisordersMental health, substance use disorderMarijuana use is associated with an increased risk of substance use disorders.JAMA Psychiatry2016
Association of Depression With Past-Month Cannabis Use Among US Adults Aged 20 to 59 Years, 2005 to 2016Mental health, depression, legalizationFollowing legalization, adults with depression had a 130% higher odds of marijuana use and a 216% higher odds of daily marijuana use. This is an increase from 46% and 37% higher odds prior to legalization.JAMA2020
Marijuana use trends among college students in states with and without legalization of recreational use: initial and longer‐term changes from 2008 to 2018Legalization, college-age marijuana useMarijuana use in colleges in states with recreational marijuana legalization increased after the enactment of legalization.Addiction2019
Consequences of Perinatal Cannabis ExposureMarijuana use during pregnancyMarijuana exposure during pregnancy and breastfeeding may alter pre and postnatal development.Trends in Neurosciences2019
Probability and correlates of transition from cannabis use to DSM‐5 cannabis use disorder: Results from a large‐scale nationally representative studyAddiction, Cannabis Use DisorderThe likelihood of lifetime marijuana users transitioning to Cannabis Use Disorder (CUD) was 27%.Drug and Alcohol Review2020
Influence of Cannabis Use Disorder Symptoms on Suicidal Ideation in College StudentsMental health, young adults, suicideAmong college students, the association between symptoms of Cannabis Use Disorder (CUD) and suicidal ideation is significant.International Journal of Mental Health and Addiction2020
Binge Drinking, Cannabis Co-Consumption and Academic Achievement in First Year University Students in Spain: Academic Adjustment as a MediatorYoung adults, co-consumption, binge drinkingFindings from a study of first-year college students in Spain indicate that marijuana co-consumption with binge-drinking was associated with lower GPA and lower academic adjustment.International Journal of Environmental Research and Public Health2020
Recreational cannabis use impairs driving performance in the absence of acute intoxicationImpaired drivingChronic, heavy, recreational marijuana use is associated with worse driving performance absent intoxication.Drug and Alcohol Dependence2020
The academic consequences of marijuana use during college.Young adult, educational outcomesMarijuana use among college students is associated with adverse college outcomes.Psychology of Addictive Behaviors2015
Marijuana Promotion Online: an Investigation of Dispensary PracticesLegalization, online advertisingMarijuana advertising online will become more common with legalization with deleterious effects and limited regulation. Prevention Science2018
Adverse Health Effects of Marijuana UseLegalization, addiction, brain development, mental health, educational outcomeLegalization may lead to increasingly adverse outcomes as more people use marijuana.New England Journal of Medicine2014
Exposure to ENDS advertising and use of marijuana in ENDS among college studentsYoung adult, vapingExposure to advertising of electronic nicotine delivery systems (ENDS) and subsequent use of ENDS contributed to the future use of marijuana in an ENDS. Addictive Behaviors2019
Youth’s Proximity to Marijuana Retailers and Advertisements: Factors Associated with Washington State Adolescents’ Intentions to Use MarijuanaYouth marijuana use; marijuana advertisingAdvertising and location of marijuana retailers influence adolescents’ intentions to use marijuanaJournal of Health Communication2020
Cannabis use prompts need for more anesthesia during surgery, increases pain and postoperative opioid useMarijuana; opioidsCannabis use prompts need for more anesthesia during surgery, increases pain and postoperative opioid useAMERICAN SOCIETY OF ANESTHESIOLOGISTS2020
Is Cannabis being used as a substitute for non‐medical opioids by adults with problem substance use in the United States? A within‐person analysisMarijuana; opioidsthe risk of opioid use DOUBLES on days marijuana is used and "suggests that marijuana is not an effective means of limiting non‐medical opioid use and casts doubt on this potential therapeutic indication."Addiction2020
Mapping cannabis potency in medical and recreational programs in the United StatesMarijuana Potency THC concentrations in marijuana products sold in marijuana storefronts in the United States are not effective for neuropathic pain relief because they contain too much THC—two to three times higher than the amount shown in studies may provide neuropathic pain relief.PLOS One2020
Psychotic disorders hospitalizations associated with cannabis abuse or dependence: A nationwide big data analysisMental health; psychosis The number of hospitalizations with a primary diagnosis of PD and schizophrenia associated with CU rose 29.4 times during the study periodInternational Journal of Methods in Psychiatric Research2020
IASP Position Statement on the Use of Cannabinoids to Treat PainMedical Marijuana and Treatment of PainThere is insufficient high-quality research to support cannabinoids as an effective treatment for pain.International Association for the Study of Pain 2021

The associations between prenatal cannabis use disorder and neonatal outcomesCannabis Use Disorder, Addiction, Pregnancystudy of nearly five million live births recorded in California from 2001 to 2012 found that babies born to mothers diagnosed with cannabis use disorders at delivery were more likely to experience negative health outcomes, including preterm birth and low birth weight, compared to babies born to mothers without a cannabis use disorder diagnosis.Addiction2021
Hits from the Bong: The impact of recreational marijuana dispensaries on property valuesMarijuana, real estate, property valuesEntry of dispensaries decreases sale prices of homes within 0.36 miles by 3–4%.Regional Science and Urban Economics2021
Trends and Characteristics of Manufactured Cannabis Product and Cannabis Plant Product Exposures Reported to US Poison Control Centers, 2017-2019Marijuana-Related Calls to Poison Control CentersUS poison centers are increasingly receiving calls about adverse events associated with exposures to manufactured cannabis products. Higher rates in legal states suggest that continued increases may be expected with adult cannabis use legalization in more states.JAMA Network Open2021