Under the Hood

Study: Teenagers Who Use Marijuana More Likely To Be Depressed, Suicidal As Adults

Using marijuana as a teenager could potentially increase the risk of developing depression in adulthood. 

A major review of 11 international studies published from the mid-nineties and data of over 23,000 teenagers found that the use of cannabis before 18 years of age increases the chance of developing depression by 37 percent in adulthood.

The findings, published in JAMA Psychiatry, linked teenage cannabis exposure to over 400,000 adolescent cases of depression in the U.S.; 25,000 in Canada; and nearly 60,000 in the U.K.

Other reviews also backed the latest findings, with some researchers suggesting that even the use of marijuana in adulthood could further increase the risk of developing depression. The new review also found that teenagers with such habit were more than three times more likely to attempt suicide. 

“Adolescent cannabis consumption was associated with increased risk of developing depression and suicidal behavior later in life, even in the absence of a premorbid condition,” researchers said. “The adolescent brain is indeed still under development and psychotropic drugs used at this time may thus alter the physiological neurodevelopment,” they added. 

To date, 20.9 percent of adolescents in the U.S. report monthly use of cannabis, while 7 percent of all high school seniors are considered daily or near-daily users, according to the study. 

With the said figures, researchers suggested that over 413,000 adolescent cases of depression in the U.S. are potentially linked to cannabis exposure.

Women or young females were found at higher risk of developing depression due to marijuana use, but those who took higher doses at earlier age also tend to have higher risks. 

The team recommended that teenagers and young adults reduce or avoid the use of cannabis due to its link to a “significant increased risk” of developing depression or suicidality.

“Our findings about depression and suicidality are very relevant for clinical practice and public health,” said study co-author Andrea Cipriani, a psychiatrist at the University of Oxford.

However, she noted that the negative effects of cannabis still vary between individual adolescents and that it is difficult to predict the exact risk for each teenager.