Is marijuana use during adolescence and early adulthood an innocent diversion or does it have serious social outcomes in later life?
This is the question addressed by Fergusson and Boden in a study they published in the journal Addiction. To obtain their answer they followed a group a young people from the age of 14 until the reached the age of 25 years. They divided these young people into six groups based on the amount of cannabis they smoked between the ages of 14 and 21 years. The rates of cannabis use among these young people ranged from none to more than 400 times during this seven year period.
Fergusson and Boden found that the more cannabis these young people used before the age of 21 years the worse off they were between the ages of 21 and 25 years. Those with the highest rate of use were the least likely to have earned a college degree, had the lowest level of income, were most likely to be unemployed, and were the least satisfied with their relationships and with life in general.
Even after statistical adjustment for a range of possibly confounding variables including: family socioeconomic status and functioning, exposure to child abuse, personal adjustment and mental health, high school achievement, and other substance use. The relationship between increasing levels of cannabis use and lower educational, economic and satisfaction outcomes remained statistically significant.
This is just another finding in a growing body of evidence that heavy cannabis use early in life can have serious consequences in early adulthood.