A study looks to add more fuel to the heated debate around the use of marijuana, as researchers have linked the frequent use of cannabis among adolescents with reduced educational attainment. The study also links frequent use of the drug with other negative health outcomes, such as suicide attempts.

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Cannabis, also commonly referred to as marijuana, can affect mood, perception and other cognitive functioning.

The study’s lead author, Dr. Edmund Silins, says that the results “provide strong evidence that the prevention or delay of cannabis use is likely to have broad health and social benefits.”

The team, comprised of researchers from Australia and New Zealand, received funding from the Australian Government National Health and Medical Research Council, and the study has been published in The Lancet Psychiatry.

Many researchers are pushing for cannabis to be used in a therapeutic capacity, as a form of pain relief or to alleviate symptoms of conditions such as multiple sclerosis (MS) and post-traumatic stress disorder (PTSD).

However, study author Richard Mattick believes that moves toward the decriminalization and legalization of cannabis also contribute toward “raising the possibility that the drug might become more accessible to young people.”

Outside of legal avenues, cannabis is the most widely used illicit drug worldwide. The National Institute on Drug Abuse (NIDA) report that around 7% of US high-school seniors are daily or near-daily cannabis users, with around 46% having tried the drug at some point during their lifetime.

Although the study uses data from adolescents in Australia and New Zealand, the authors state that the rates of cannabis use are similar across high-income countries. For example, they cite that the rates of cannabis use among adults in Australia and New Zealand are 10% and 15% respectively, compared with a rate of 15% in the US.

For the study, the researchers utilized the data of 3,765 participants from three large, long-term longitudinal studies, tracking cannabis use alongside several developmental outcomes from before the age of 17 up to the age of 30.

They recorded the frequency of cannabis use as never, less than monthly, monthly or more, weekly or more, or daily. The researchers chose to record the following developmental outcomes:

  • Cannabis dependence
  • Completing high school
  • Depression
  • Obtaining a university degree
  • Suicide attempts
  • Use of other illicit drugs
  • Welfare dependence.

The researchers found significant associations between the frequency of adolescent cannabis use and all of the designated developmental outcomes. After adjusting for potential confounding factors such as socioeconomic status and mental illness, they found that five of the associations remained significant.

Individuals who had used cannabis daily before the age of 17 were 60% less likely to complete high school or obtain a degree than those who had never used cannabis. They were also 18 times more likely to become dependent on cannabis, eight times more likely to use other illicit drugs and seven times more likely to attempt suicide by the age of 25.

Most significantly, the researchers found that the risk of negative developmental outcomes increased relative to the frequency of the cannabis dose. Daily cannabis users experienced the strongest effects of the association.

In a linked commentary, Prof. Merete Nordentoft, of the University of Copenhagen, Denmark, explains why these results may have occurred:

Persistent cannabis use has adverse effects, such as low energy and initiative, and impairment of cognitive functions, and these factors are likely to mediate the harmful effect of cannabis on educational attainment.”

The authors say that these findings are consistent with the results of previous studies investigating early cannabis use alongside these developmental outcomes. They suggest that preventing or delaying cannabis use in adolescents could have far-reaching benefits, both socially and with regard to health.

One measure that the authors suggest could be implemented is screening for cannabis use in adolescents as standard practice during visits to doctors, child psychiatrists, school nurses and other health care practitioners. This is due to an estimated lack of self-reporting among adolescent cannabis users.

“Efforts to reform cannabis legislation should be carefully assessed to ensure they reduce adolescent cannabis use and prevent potentially adverse effects on adolescent development,” says Dr. Silins.

In spite of this, the authors also acknowledge that within US states where cannabis has been made increasingly available for medical use, there has been no reported increase in use among young people.

The study still urges caution. The landscape is undeniably changing with regard to how cannabis is perceived and utilized, and the authors believe that as this framework changes, the needs of the youth must always be considered in order to prevent adverse developmental outcomes.

Recently, Medical News Today reported on a study that suggested women could be more susceptible to the effects of cannabis.