Pattern of Marijuana use During Adolescence may Impact Psychosocial Outcomes in Adulthood

A new study completely by the University of Pittsburg and published in the journal Addictionhas found that a pattern of marijuana use during adolescence may impact psychosocial outcomes in adulthood. As reported by the lead author of the study, Erika Forbes:

“We know that cannabis use in adolescence is associated with outcomes like lower educational level, and difficulties with mood and depression, but through this long-term study, we’ve been able to provide a much deeper insight into this relationship, showing that certain characteristics of use may be more important than others…The findings highlight that understanding marijuana use across the entire period of adolescence, which we know is an extremely vulnerable developmental phase, may tell us much more about detrimental long-term impacts than knowing about overall or one time use.”

The Study Details

Over 158 boys were studied under the study. All the boys were a part of the Pitt Mother and Child Project, a study of males at high risk for anti-social behavior. The brains of the adolescents were scanned using fMRI to access functional connectivity and a number of questionnaires were also to be completed from the boys aged between the ages of 20-22. The researchers analyzed cannabis use from the ages of 14-19 and assessed the relationship between cannabis use and physiological outcomes. What the researchers found was that those who started to take cannabis between the ages of 15-16 with frequent use by the time they were 19 had the greatest dysfunction in brain reward circuitry. They also had the highest rates of depression and the lowest academic achievements. The study is not ambiguous, and has found that early users of marijuana have lower academic scores and greater rates of depression. This effect is more pronounced when users start to use marijuana early as opposed to in later years.


There are a number of things to be considered when analyzing such research articles. First, is that this is a tiny sample set of boys who are already not in the best environment, and not in the best area. So the sample set has a number of people already predisposed towards crime, depression and low academic achievement. They were already in the Pitt Mother and Child Project. So of those who are already undergoing psychological problems those youths who take marijuana at an early age will get lower scores and be at greater risk of depression. This may not hold for youths across the country.

There is the obvious point that is glossed over, which is that people who are more likely get low scores and feel depressed are more likely to start smoking marijuana, as they come from poorer and more disadvantaged backgrounds. The research has it backwards. People who are more likely to get low test scores and feel depressed are more likely to engage in marijuana. Marijuana is not the causal link for low test scores and the depression, and the study researchers admit there is no causal link established between marijuana use and the implied outcomes.

Aside from this, the subject size is too small to derive any meaningful conclusions. Then there is the serious question as to study design and methodology. A mete analysis conducted by John Ioannidis has found that up to 50% of published research findings are false, and there are often serious design errors and incorrect conclusions drawn, such as the one above -that a pattern of marijuana use during adolescence may impact psychosocial outcomes in Adulthood. The idea is that marijuana use in adolescents is going to result in lower test scores which is going to have a severe impact on the lives of these children. When it is probably more appropriate to say that poverty levels which arise due to illogical government policies result in lower test scores and increased marijuana use among adolescents.

The Takeaway

There are many questionable studies coming out which want to indicate that marijuana is terrible for everyone’s health, and they fall apart on further investigation. However, marijuana should not be overused or it will have consequences. Like anything external to the body, over reliance will lead to dependency, and adolescents are particularly vulnerable. It is a scientific fact that when receptors in the brain are frequently stimulated, they get less dense. Which means that it is the brain receptors that come to rely on the marijuana downregulate in order to align with the expected dose of THC. So when you don’t have your THC the receptors are still downregulated, and you are a little less sharp and focused. In other words, marijuana may be more of a trade off as opposed to the THC gift that keeps on giving.

The takeaway is that marijuana is perfect for those suffering from medical conditions or a couple of times a week for those who need some rest and relaxation. But smoking a couple of joints every day is going to have consequences, at some stage in life.

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