With Marijuana being legalized in some parts of the world, either for medical or recreational purposes, there has been a widespread increase in its availability. Corresponding to this increased availability is a surge in its consumption.

To understand the impact of this increased availability and consumption, and to establish links between the continuous use of marijuana resulting in a range of psychological disorders, there are numerous on-going studies and research projects being conducted. With findings that suggest strong enough evidence to warrant a public health message to warn against the impact of cannabis use leading to psychotic disorders, further research is needed to delve deeper into the magnitude of the problem.

Links between marijuana and psychosis

There are a range of arguments for and against the link between marijuana use and an increase in psychosis. More recently, 10 research studies, published in the journal Biological Psychiatry, were conducted to establish links between long-term marijuana use and psychotic disorders. Seven of them proved strong links between the two.

Age and marijuana

Continued research has gone on to prove that high-potency marijuana has variable impacts on users belonging to different age groups, making it one of the leading causes of mental health disorders.

Continued use of marijuana increases the risk of psychosis in users where their thoughts and emotions are impaired to an extent that a person loses all contact with their external reality. For young adolescents who take to chronic marijuana consumption, users are at a higher risk of psychosis and other mental health disorders, as their brains are far more vulnerable to structural and functional changes. This has been correlated with users in urban areas, prone to gun violence. This is especially troubling in places that have instituted a stand your ground law, which could put cannabis using adolescents at greater risk of death.

This is especially true because this is the stage of critical brain development in young people, placing those adolescents with pre-existing vulnerability at a higher risk.

Relevant studies have also pointed to the onset of psychosis in young marijuana consumers nearly four years earlier than young adults with no history of marijuana use.  With the legalization of marijuana as a recreational drug, many do not perceive of it as harmful anymore, hence the increased intake, particularly among young adults.

Increased marijuana use amongst adolescents also affects performance in school, heightens academic failures and incidents of school dropouts, along with addiction issues.

How THC ups the risk of psychosis

An increased risk of psychosis has been found in users who've consumed marijuana containing a higher strain of Tetrahydrocannabinol (THC) than those who use weaker strains of the drug. THC is what gives the so-called 'high' to users who smoke or ingest marijuana.

There is a proven link between THC and psychosis, reinforcing the fact that it isn't mere coincidence. There is also reason to believe that THC hampers the brain's ability to differentiate between important stimuli versus those that are not. These are known scientifically as abnormal 'salience attribution'.

On the other hand, the compound cannabidiol (CBD), found in cannabis, is known to decrease the symptoms caused by THC and have antipsychotic effects. Studies suggest that CBD may even be used in as a therapeutic option to treat psychosis.

The dose-response relationship

The use of marijuana causes an increased risk of psychosis. That's the bottom line. But it's important to understand the relationship between level of marijuana use and the corresponding risk of psychosis and other mental health disorders like schizophrenia.

The frequency and potency of marijuana is what is ultimately associated with the risks of mental health disorders. While any use of marijuana ups the risk of psychosis by about 40% more than non-marijuana users, the higher the frequency of intake, the stronger and more severe are the symptoms of psychosis and psychotic disorders. Those ingesting marijuana on a daily basis, multiple times a day, put themselves in the highest risk category of susceptibility to psychosis, two or three times more than non-smokers. Prolonged use will bring about the onset of psychosis, while cutting down or stopping the use of marijuana altogether will improve and lessen the symptoms of mental health issues.

Another thing to keep in mind is a predisposition to psychosis brought about by factors such as family history and immediate surroundings. This may also impact the onset of psychosis in users who become more vulnerable to this illness, aided of course, by the consumption of marijuana. The risk is higher with individuals who carry a specific risk gene, catechol-O-methyltransferase (COMT), which is known to make users more receptive to the onset of psychosis, if they are marijuana users.

With more countries and states legalizing the use of recreational marijuana, and its availability spreading far and wide, the need of the hour is to educate users on the pros and cons of this herbal drug.

Awareness about the long-lasting psychological effects of this drug needs to be made available to users to make informed decisions about usage, dosage, frequency and potency of the drug.