While cigarette smoking has long been on the decline, marijuana use is on the rise and, disproportionately, marijuana users also smoke cigarettes. A new study by researchers at Columbia University’s Mailman School of Public Health and the City University of New York reports that cannabis use was associated with an increased initiation of cigarette smoking among non-cigarette smokers. They also found adults who smoke cigarettes and use cannabis are less likely to quit smoking cigarettes than those who do not use cannabis. Former smokers who use cannabis are also more likely to relapse to cigarette smoking. Results are published online in the Journal of Clinical Psychiatry.

Until now, little was known about the association between cannabis use and smoking cessation or relapse over time in the general adult population.

The analyses were based on data from the National Epidemiologic Survey on Alcohol and Related Conditions in 2001–2002 and 2004–2005, and responses from 34,639 individuals to questions about cannabis use and smoking status.

“Developing a better understanding of the relationship between marijuana use and cigarette use transitions is critical and timely as cigarette smoking remains the leading preventable cause of premature death and disease, and use of cannabis is on the rise in the US,” said Renee Goodwin, PhD, in the Department of Epidemiology at the Mailman School of Public Health, and senior author.

The study suggests that marijuana use—even in the absence of cannabis use disorder (characterized by problematic use of cannabis due to impairment in functioning or difficulty quitting or cutting down on use)—is associated with increased odds of smoking onset, relapse, and persistence. As cannabis use is much more common than cannabis use disorder, its potential impact on cigarette use in the general community may be greater than estimates based on studies of cannabis use disorder alone, according to the researchers.

An earlier study by Goodwin and colleagues showed that the use of cannabis by cigarette smokers had increased dramatically over the past two decades to the point where smokers are more than 5 times as likely as nonsmokers to use marijuana daily.

Goodwin advises that additional attention to cannabis use in tobacco control efforts and in clinical settings aimed at reducing cigarette smoking and smoking-related negative consequences may be warranted. She also points out that understanding the potential links between cannabis use and cigarette initiation in youth is needed given that recent data suggest cannabis use is more common among adolescents than cigarette use.