With the legalization of cannabis comes a host of new concerns.
Both legal and public opinion of cannabis is changing in America.
Today, in Alaska, Colorado, Oregon and Washington, the possession and sale of cannabis for medicinal and non-medicinal purposes is legal.
Alongside these four states, another 15 are considering legalizing recreational cannabis use.
Washington, DC, legalized the personal use (but not commercial sale) of cannabis in 2015.
And a national survey conducted in 2013 found that 52% of Americans thought marijuana should be made legal.
As the law steadily softens across the country, research into the long-term effects of cannabis is more important than ever.
Cannabis research on the rise
There are few areas of medical investigation as controversial as cannabis research, but previous studies into the social impact of cannabis have yielded contradictory or unclear findings.
Despite these controversies, a study team, led by Magdalena Cerdá at the University of California, recently conducted a thorough investigation into the social and economic aspects of heavy cannabis use.
Alcohol abuse is more likely than cannabis to play a role in events such as traffic accidents and violence. However, when cannabis and alcohol's effects on relationships, delinquency and education are measured, results are less conclusive.
The number of potential factors to consider are vast, making results difficult to analyze and interpret. These factors include the likelihood of cannabis and alcohol users to abuse other drugs; also, the illegal status of cannabis means that users might be tied to other illegal activities, or incarcerated, both of which have negative consequences unrelated to cannabis itself.
Additionally, heavy cannabis use from an early age might have its roots in underlying psychopathology or preexisting social or economic problems at home.
Cerdá's research attempts to head off as many of these confounding variables as possible.
A fresh look at the impact of cannabis
The study, published in Clinical Psychological Science, uses data from the Dunedin Multidisciplinary Health and Development Study that followed 1,037 New Zealand children from birth until the age of 38.
The financial consequences of cannabis abuse might be worse than alcohol.
The group represented a cross-section of the population and received a maximum of 11 follow-up assessments over the years.
For the current study, the researchers utilized data from 947 individuals.
In total, 18% of participants were considered marijuana-dependent in at least one of the assessments, and 15% were classified as regular cannabis users in at least one assessment.
According to Cerdá, the team 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."
"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."
These findings remained constant even after controlling for factors such as childhood socioeconomic problems, lower IQ scores, depression and antisocial behavior in adolescence, lower motivation to achieve, higher levels of impulsivity, criminal convictions and the abuse of alcohol and other drugs.
Alcohol, lesser of two evils?
The results showed that both alcohol and cannabis abusers experienced similar declines in social class; they were both more likely to carry out antisocial behaviors in the workplace and to have relationship problems.
However, the heavy cannabis users were more likely than the alcohol abusers to have severe financial difficulties; for instance, they more regularly reported difficulty finding enough money to enable them to eat.
Moffitt, a psychologist at Duke University and the Institute of Psychiatry at King's College London, UK, sums up the findings: "Cannabis may be safer than alcohol for your health, but not for your finances."
These results and others like them are increasingly important as the legal status of cannabis shifts. As Cerdá says:
"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."
The researchers are quick to remind readers that their research "does not support arguments for or against cannabis legalization," their results simply show that "cannabis was not safe for the long-term users tracked" in their study.
Although results from previous investigations have been contradictory, this study has paid particular attention to the detail and offers a deeper insight into the long-term social and financial implications of cannabis abuse.
Further research is sure to follow, and the picture will grow clearer with time. Medical News Today recently covered research investigating cannabis' effect on the processing of emotions.