The effects of cannabis use have been heavily debated over the past few years as individual states within the U.S. have been slowly legalizing the medicinal use of the substance. Although some studies have found that marijuana can have a therapeutic effect on people with different health conditions, a new study suggests that smoking too much weed can end up hurting one's social and financial status.
"Our research does not support arguments for or against cannabis legalization," said lead investigator Magdalena Cerdá at the University of California, Davis, Health System. "But it does show that cannabis was not safe for the long-term users tracked in our study."
For this research, the international team, which included Avshalom Caspi and Terrie Moffitt at Duke University, set out to examine the long-term effects of excessive and persistent marijuana use. The researchers looked at data on 947 out of 1,037 people from the Dunedin Multidisciplinary Health and Development Study. The participants were born from 1972-1973 in Dunedin, New Zealand. All of the participants were tracked from when they were born and to the age of 38. There were a total of 11 follow-up examinations.
After assessing cannabis use and dependence, the researchers found that 173 participants, or 18 percent, could be categorized as marijuana dependent, and 140 participants, or 15 percent, could be grouped as regular cannabis users in at least one time frame within the study.
The researchers found that people who smoked weed at least four days a week over several years were more likely to have a lower social class than their parents. This group of smokers tended to have lower-income jobs that were considered to be less skillful and less prestigious. They were also more likely to have money, work and relationship problems.
"Our study found that regular cannabis users experienced downward social mobility and more financial problems such as troubles with debt and cash flow than those who did not report such persistent use," Cerdá said. "Regular long-term users also had more antisocial behaviors at work, such as stealing money or lying to get a job, and experienced more relationship problems, such as intimate partner violence and controlling abuse."
The researchers added that these social and economic problems remained even after they factored in variables, such as IQ (intelligence quotient), criminal history, socioeconomic problems in childhood and depression.
"These findings did not arise because cannabis users were prosecuted and had a criminal record," said Caspi. "Even among cannabis users who were never convicted for a cannabis offense, we found that persistent and regular cannabis use was linked to economic and social problems."
When the researchers compared cannabis use to alcohol use, they found that the effects from both drugs were generally the same with one exception: cannabis use had a greater negative effect on one's finances.
"Cannabis may be safer than alcohol for your health, but not for your finances," Moffitt said.
"Alcohol is still a bigger problem than cannabis because alcohol use is more prevalent than cannabis use. But, as the legalization of cannabis increases around the world, the economic and social burden posed by regular cannabis use could increase as well," Cerdá added.
The study's findings were published in the journal Clinical Psychological Science.
