"One only has to examine the devastating impact felt in Colorado since 2013, when recreational use of marijuana was legalized, to fully grasp what would be in store in Massachusetts," the statement says, noting that traffic deaths have increased 48 percent since the drug was legalized.

"Recent statistics show that of all traffic deaths in Colorado, 21 percent of those individuals killed tested positive for marijuana. Marijuana related hospitalizations in Colorado have doubled from 2011 to 2014," it continues.

Additionally, "Marijuana use and abuse by the youth of Colorado has increased by 20 percent since legalization. Young people in Colorado rank first in the nation for marijuana use -- an illegal activity for anyone under the age of 21."

"Strikingly, this has negatively affected their family life, social life and school performance where expulsions and drop-out rates have spiked significantly. Do we really want to bring these issues to Massachusetts?" the bishops wrote.

The bishops also cited Church teachings, writing that "the Catholic Church teaches 'the use of drugs inflicts very grave damage on human health and life. Their use, expect on strictly therapeutic grounds, is a grave offense.'"

Speaking with The Pilot Oct. 4, MCC executive director James Driscoll said that he believes there will be a "groundswell of opposition" against the ballot question as the election approaches.

He noted that prominent public officials, including Gov. Charlie Baker and Boston Mayor Martin Walsh have spoken out against legalizing the recreational use of marijuana, as have all of the district attorneys and sheriffs in the state.

"I think you'll start seeing more and more leaders both in the medical field, the political world, the religious leaders, all banding together to come out and say 'Take a step back. Is this a good thing for Massachusetts?'" he said.

"We're hoping the answer most of the voters come to is no, it's not a good thing," he added.