2019 study: A large study finds pot use "strongly linked" to developing schizophrenia and paranoia with 20% of new psychosis cases associated with daily marijuana use; that percent skyrockets to 30% and 50% in London and Amsterdam with their higher average THC content, reports the journal Lancet.

2019 study: Five years of recreational legalization has tripled Colorado's already high emergency room pot visits, per the journal Annals of Internal Medicine for heart trouble, uncontrollable vomiting, and psychotic episodes.

2019 study: After the studies (below) showing how pot mutates DNA to potentially harm even offspring, now the Journal of Urology reports that marijuana significantly harms sperm production. 

2018 study: Half of all first-time patients admitted for drug treatment worldwide are for cannabis, which therefore is even more than for heroin and cocaine combined, according to Psychological Medicine. 

2017 study: Violence was two-and-a-half-times more likely from pot-smokers discharged from psychiatric hospitals than from others. Canadian researchers studying U.S. patients ruled out other possible explanations such as alcohol contribution or that perhaps "violent people use cannabis", published in Frontiers in Psychiatry. 

2017 study: Bristol University researchers peer-reviewed study of 5,000 youths found that teens who regularly smoke pot are 26 TIMES more likely to begin using other drugs by age 21, and they're 37 TIMES more likely to be addicted to nicotine and 3 TIMES more likely to have an alcohol problem, all as compared to teens who don't smoke marijuana.

2017 study: The Journal of Neuroscience is identifying at the cellular neuron level how pot causes addiction and strongly interferes with the brain's sophisticated physiological reward system, which could be why Miley Cyrus and Woody Harrelson recently quit smoking dope.

2017 study: Pot smokers are four times more likely to get a heart attack, etc., says a Case Western Reserve study of 210,000 cannabis smokers compared to ten million non-users.

2017 study: Colorado's Children's Hospital, in a post-legalization study, saw teens with marijuana intoxication or who tested positive for pot increase from 146 in 2005 to 639 in 2014. Unlike teens answering surveys, blood tests don't lie.

2017 study: Quest Diagnostics, mega workplace-testing lab, reports 2016 drug use up nationwide and single-year increases in the "legalization" states Washington, up 9 percent, and Colorado, up 11 percent.

2017 study: Highway Loss Data Institute reports that from 2012 to 2016 car crashes are up in decriminalization states. Oregon 4%; Washington 6%; Colorado 14%, as compared to neighboring states, including as THC-involved crashes soar.

2017 study: College students with decriminalized access to pot significantly lower their grades per the Review of Economic Studies.

2016 study: ALL 1,000 U.S. pot smokers studied in a Journal of Alzheimer's Disease paperhad "low blood flow" throughout the brain and, tragically, restricted blood flow in the brain's memory/dementia region

2016 study: The UK's Daily Mail headlines their article on a paper in the journal Clinical Psychological Science, "The more cannabis you smoke, the more likely you are to be a loser"

2016 study: Research explains how pot mutates your DNA and why smoking it leads to disease including cancer, all validating a 2009 study

2016 study: Science News reports "Marijuana use weakens heart" from a paper in an American Heart Association peer-reviewed science journal and were about twice as likely as non-users to suffer depression, psychosis, anxiety disorder, etc.

2016 study: Just one minute of (even only) secondhand marijuana smoke may damage blood vessels, is three times worsefor arterial walls than cigarette smoke, and endangers lungs and heart and can lead to attack, clots, and stroke, and yet, per the journal Nature, 16% of Colorado one-year-olds with bronchiolitis test positive for THC exposure. Tragic. 

2016 study: The Journal of the American Medical Association (JAMA) Ophthalmology reports that smoking pot harms eyesight by damaging the nerves that connect your retinas to your visual cortex

2015 study: Strong pot yields hallucination, paranoia & schizophrenia in a nearly a quarter (24%) of those newly diagnosed, per Lancet Psychiatry

2015 study: at Nature.com, current and former pot users perceive a false reality; impaired hippocampus harms memory used "to solve common problems and to sustain our relationships"

2015 study: 100 varieties of pot appear to "damage nerve fibres that handle the flow of messages across the two halves of the brain" per a study in Psychological Medicine 

2015 study: JAMA Psychiatry reports that over the last decade, pot use in the U.S. more than doubled to nearly 10%, or 22 million people, with the huge study finding obvious signs of dysfunction from marijuana use in more than 7 million people

2015 study: Drug and Alcohol journal: pot impairs driving just like alcohol

2015 study: Pot harms brain imaging shows regarding learning and memory, presented at the Society of Nuclear Medicine and Molecular Imaging Annual Meeting

2014 study: in PNAS, pot users have shrunken brains and lower IQ

2014 study: 20 years of research reported on by WHO advisor Prof. Wayne Hall shows pot doubles mental impairment, psychosis; increases drop out, tobacco smoking, car crash, and rates of other illicit drug use.  

2014 study: large Lancet study shows high schoolers 63% less likely to graduate, 8-fold increased odds of using other illegal drugs, and 7-fold increased likelihood of attempted suicide (like Heisman trophy winner's)

2012 study: Landmark study in PNAS: pot permanently lowers IQ

2012 study: Netherlands study of 2,000 teens show pot/psychosis link

2012 study: The journal Pharmaceuticals associates marijuana use with Cyclic Vomiting Syndrome

2010 study: Netherlands study shows marijuana may stunt fetal growth

2009 study: American Chemical Society reports, marijuana damages DNA and may cause cancer

2009 study: Pot during pregnancy predicts long-lasting neurobehavioural problems for the child

2008 study: Marijuana smoker faces rapid lung destruction, 20 years ahead of tobacco smokers

2007 study: New Zealand study of impact on lungs from one joint equaling three to five cigarettes

2007 study: Canadian study shows pot smoke contains higher levels of various toxins than tobacco smoke

2007 study: Harvard finds that marijuana component opens the door for cancer virus for Kaposi's Sarcoma

2006 study: The journal Neurology reports that marijuana causes learning and memory impairments

2005 study: New Zealand study reports habitual marijuana use strongly associated with car crash injury

2005 study: French National Institute for Transport and Safety Research shows pot doubling fatal crashes

2004 study: Hungarian Neuropsychopharmacologia journal reports schizoid psychosis from smoking pot

1989 study: In the U.S., from back when it was weaker, pot associated with impaired fetal growth 

Drugs.com: nursing mom smoking pot passes THC, etc. to her child; can harm baby's motor development

By 2013 the Denver Post still hasn't come out of their stupor but at least they've noticed the fog. Sad but important insights on the long lasting harm from smoking pot as described by Dr. Kari Franson, professor from the University of Colorado's School of Pharmacy and Pharmaceutical Sciences. (Notice the Post uncritically quoting a pot dealer who speaks of his customers as his "patients".)