A new study suggests that those who smoke marijuana during their early teens are at greater risk of suffering from depression later in life.
It’s important to note that the study didn’t identify marijuana as the cause of the depression, only that youngsters who smoke it are more likely to develop depression and depression related conditions than those who don’t.
The study which was published in the American online Journal of Epidemiology, involved researchers looking at data concerning more than 50,000 adults spanning 17 different countries, all who took part in a World Health Organisation (WHO) study into mental health.
The results showed a moderate association between smoking marijuana before reaching the age of 17 and developing depression, and a 50 percent increase in the risk of developing a depressive episode after the age of 17 if marijuana was smoked before they reached 17.
However, the association was somewhat weakened when the researchers took into account childhood problems like playing truant, shoplifting and getting into fights.
Lead Researcher in the study, Dr. Ron de Graaf, of the Netherlands Institute of Mental Health and Addiction in Utrecht, told Reuters Health in an email that this type of conduct could “partially” explain the relationship between early marijuana use and later depression.
The study did have limitations, one of which was that the screening for depression took place only at one single point in time and didn’t follow the participants over a period of time. As such, it isn’t clear whether the depression came first, or the use of marijuana.
The results came from the participants self reported symptoms of a depression spell that lasted for at least two weeks and they had to remember when that occurred.
Around 9,647 of those who took part said they were over the age of 17 when they had their first “spell” of depression and around 41,000 said they had not experienced a spell of depression.
Of those who had experienced depression, 9 percent had smoked marijuana before reaching the age of 17 whereas only 7 percent of the control group had. The indications are that in general, if you smoke marijuana before you are 17 you have a greater chance of developing depression later in life.
“Early cannabis (marijuana) use may have important consequences for later mental health,” de Graaf told Reuters.
De Graaf does acknowledge that more studies are needed, particularly those that follow young people over a period of time.
