Marijuana- What's next?

It seems to be a cultural way of maturation but without the consideration of the consequences. Someone told me that its use is so common that those who do not smoke it are seen as the odd one out in most colleges. My main concern is the effect it has on the mental health of these young people.  This issue became of importance to me when two young people close two me ended up having mental issue in their late teens. Both were users of marijuana before the mental break up. I decided to do some investigation to find out whether there was any research on this issue. My investigation did confirm that there is indeed research confirming my suspicion. 

The use of street drugs, including LSD, methamphetamine, cannabis and alcohol has been linked with significantly increased probability of developing schizophrenia. This link has been documented in over 30 different scientific studies done mostly in the United Kingdom, Australia and Sweden over the past 20 years. One study interviewed 50,000 members of the Swedish Army about their drug consumption and followed up with them later in life. The study established that those who were heavy consumers of cannabis at age 18 were over 60% more likely to be diagnosed with schizophrenia over the next 15 years than those who did not take it. Experts now estimate that between 8% and 13 % of all schizophrenia cases are linked to cannabis use during teen years.

Many of these research studies indicate that the risk is higher when the drugs are used by people under the age of 21 years, a time when the human brain is developing rapidly and is particularly vulnerable. This risk is highest on people with a biological disposition towards schizophrenia. Researchers in New Zealand found that those who used cannabis by the age of 15 were more than three times more likely to develop mental illnesses such as schizophrenia. Other similar research has backed these findings showing that cannabis use increases the risk of psychosis by up to 70% for heavy users, and that the risk increases in proportion to the amount of cannabis used. The younger a person smokes or uses cannabis, the higher the risk for schizophrenia, and the worse the schizophrenia is when the person does develop it.

Robin Murray, at the London Institute of Psychiatry did a study in 2005 with more than 750 adolescents in conjunction with colleagues at King’s college London and the University of Otago in New Zealand. The study established that overall people were 4.5 times more likely to develop schizophrenia at the age of 26 years if they were regular users of cannabis at age 15 compared to 1.65 times for those who did not report regular use until age 18. Researchers now believe that using the drug while the brain is developing boosts levels of the chemical dopamine in the brain which can directly lead to schizophrenia.

Another study was done to establish the trends in cannabis use prior to first presentation with schizophrenia in South East London between 1965 and 1999. The rate of cannabis use in the year prior to first ever presentation was measured over seven times periods. The conclusion for the study was that cannabis use in the year prior to presentation with schizophrenia increased markedly between 1965 and 1999, and disproportionately so compared to increase in cannabis use on other psychiatric disorders.

A clinical toxicologist at Imperial College London, Professor John Henry, says that research has shown that people with a certain genetic makeup who use the drug face a ten times risk of schizophrenia. The increased risk applies to people who inherit variants of a gene named COMT and who smoked cannabis as teenagers. About a quarter of the population has this genetic make-up and up to 15% of the group is likely to develop psychotic conditions if exposed to cannabis early in life. Neither the drug nor the gene raises the risk by itself.

Professor Castle, author of the book Marijuana Madness (2004), has suggested that people with “psychotic proneness” were those who had a family history of mental illness or who had a bad response on their first use of cannabis or to a tiny amount.  Without the effects of drug, such persons might live their whole life without experiencing mental health problems. It is estimated that between 8% and 13% of people that have schizophrenia today would never have developed the illness without exposure to cannabis. Cannabis impacts on neurotransmitters that regulate how arousal and stress are managed in the brain. Cannabis takes a long time to metabolize, and can quickly build up to high levels in the body. It’s at this point that the risk of depression or schizophrenia is triggered.

This is evidence that cannot be ignored yet society seems to glamorize the culture and ignore these factors. I am aware that cannabis can be used for medicinal purposes, and I am not questioning that. But that aside one cannot ignore this kind of data if we truly care about the future condition of the next generation. The mental health profession is also not very vocal in warning when it comes to this issue which is very sad.