A study by the Agency for Healthcare Research and Quality (AHRQ) found that in 2011, sedatives and hypnotics were a leading source for adverse drug events seen in the hospital setting. Approximately % of all ADEs present on admission and % of ADEs that originated during a hospital stay were caused by a sedative or hypnotic drug.  A second study by AHRQ found that in 2011, the most common specifically identified causes of adverse drug events that originated during hospital stays in the . were steroids, antibiotics, opiates/narcotics, and anticoagulants. Patients treated in urban teaching hospitals had higher rates of ADEs involving antibiotics and opiates/narcotics compared to those treated in urban nonteaching hospitals. Those treated in private, nonprofit hospitals had higher rates of most ADE causes compared to patients treated in public or private, for-profit hospitals. 
Yes, of course very heavy use of marijuana can be damaging. Some are escaping to not join reality.
However: Nitrogen is poisonous in excessive amounts. So is water. What you are looking at there are basically megalomaniacs. I have also seen latent schitzophrenia come to surface sooner. Look at it this way; Maybe it is better to find out the disease exists sooner for some. A young man in Duluth MN hadn't ever used mephrodone. He purchased from a head shop and did them all at once, suffered a coma and brain and nervous system damage..... Maybe we should put Drano on the list? Idiodiocy will kill anyone with nearly anything.
Most drugs of abuse are addictive. Addiction is a chronic, relapsing disease characterized by compulsive drug seeking and use despite negative consequences and by long-lasting changes in the brain. People who are addicted have strong cravings for the drug, making it difficult to stop using. Most drugs alter a person’s thinking and judgment, which can increase the risk of injury or death from drugged driving or infectious diseases (., HIV/AIDS, hepatitis) from unsafe sexual practices or needle sharing. Drug use during pregnancy can lead to neonatal abstinence syndrome, a condition in which a baby can suffer from dependence and withdrawal symptoms after birth. Pregnancy-related issues are listed in the chart below for drugs where there is enough scientific evidence to connect the drug use to negative effects. However, most drugs could potentially harm an unborn baby.