A growing number of experts have been questioning the role of marijuana as a therapeutic and recreational drug for chronic pain patients.

They say there are no studies to support marijuana’s potential to treat chronic pain.

A new report from the National Institutes of Health (NIH) has put that to rest, concluding that marijuana does not appear to cause a significant increase in the risk of cancer and that studies show it does not increase the risk for other serious diseases.

The study found that the only cancer-related cancers detected among people who reported use of marijuana were lung, colon and breast cancer.

It said the study “does not support a causal relationship between marijuana use and these cancers.”

The study is the first to specifically investigate the potential role of the plant in cancer prevention, but it does raise the question of whether there is a real connection between marijuana and the types of cancers it has been linked to.

While many of the cancers studied are on the order of mild, the authors say, “there is no evidence that marijuana use causes cancers of the mouth, throat, esophagus, liver or prostate.”

The National Institutes report also says marijuana has “no effect on the development of the chronic obstructive pulmonary disease, COPD, asthma, multiple sclerosis, or amyotrophic lateral sclerosis.”

The authors also found that while marijuana may have a role in the development and progression of multiple sclerosis and amyotrophoma, it does have no effect on other cancers, including those of the breast and colon.

A few other studies have found a link between marijuana abuse and cancer, but the NIH study is a first to link marijuana use with any of the three major types of cancer.

The American Cancer Society, the American Cancer Foundation and the National Cancer Institute are among the organizations that have previously criticized the NIH’s conclusions.

The American Cancer Association has called the findings “a disappointing failure.”

“The NIH has not been able to demonstrate that marijuana is a significant risk factor for these cancers,” the association said in a statement.

The NIH also says that the study has a number of limitations.

It is based on surveys that were collected between 2007 and 2013.

Some of those were done in New York City, where marijuana is legal, but others were done elsewhere, such as Colorado.

It also relied on self-reported data, rather than laboratory testing.

The study authors did not conduct any of those studies themselves.

They also say that there is no way to measure how much marijuana use has changed a person’s cancer risk since they began using it.

The findings have implications for how the U.S. government approaches its war on marijuana, which the administration has said it plans to take to court, if it is allowed to go into effect.

The federal government has been trying to get states to allow the sale of marijuana to adults 21 and older for a number years, but states have struggled to find the money to license shops.

As a result, the drug has been tightly controlled by state authorities, and only about 15 percent of the states have approved the use of recreational marijuana.