Smoking marijuana may be more harmful to lungs than smoking cigarettes, study finds

As recreational pot has gained traction in states all across the country, more research has been focusing on its health effects. One argument marijuana supporters have stood by for years - that weed is healthier than cigarettes - is now coming under fire.

A new study has found that smoking marijuana may be more likely to cause certain health problems than tobacco.

"Perhaps it's time to just pause and think about what you're doing to yourself until we get more information," said Dr. Scott Brandman, a thoracic radiologist, in reference to the new study published in the Radiological Society of North America.

That study reviewed lung scans of smokers and found that rates of emphysema, airway inflammation and enlarged breast tissue were higher in marijuana smokers than tobacco smokers. Emphysema is already the third leading cause of death in America.

"Marijuana smoke not only damages the airways in the lung... but it's actually making holes in it," Brandman explained. "We're seeing for the first time these holes being created in the lung. That is going to be irreversible damage for these people."

The Centers for Disease Control and Prevention say about 20% of all Americans have tried pot. It's also the most commonly used drug in America that is still illegal at the federal level.

Brandman says one factor that may affect weed smokers is how they inhale: deeper, holding the smoke in their lungs longer.

"It's going deeper into the lung and its having an opportunity to stay there for a longer time during that deeper, longer breath hold," he said.

And researchers are also looking at something within pot.

"There's a carcinogen or chemical that we haven't yet identified in marijuana smoke, that we're theorizing is damaging the lung and creating these holes," Brandman added.

If you're using marijuana for medical reasons, Brandman suggests talking to your doctor about edibles or ways other than smoking to use marijuana.

Some health effects of marijuana, such as brain development issues, high blood pressure, and increased risk of heart attacks and strokes, have been studied. However, according to Dr. Albert Rizzo, lung doctor and chief medical officer of the American Lung Association, "We don't know the long-term effects of marijuana as we do for the long-term effects of tobacco."

Tobacco smoke is also filtered, but marijuana smoke is not. All of these factors contribute to inflammation and irreversible damage, doctors say.

"Anything you inhale that could irritate the lungs would not be advisable, so I would recommend they stop," Rizzo said. However, he recognizes that some users have medical necessity.

"There is a public perception that marijuana is safe. This study signals that marijuana could be more harmful than people realize," said Dr. Giselle Revah, study co-author and cardiothoracic radiologist.

ABC News contributed to this report.