Story highlights White House press secretary Sean Spicer seemed to tie recreational marijuana to the opioid crisis

Many experts argue that he may have gotten the opioid epidemic wrong

(CNN) As White House press secretary Sean Spicer spoke Thursday about "greater enforcement" of federal marijuana laws, he seemed to link recreational pot use to a different type of drug: opioids.

"I think that when you see something like the opioid addiction crisis blossoming in so many states around this country, the last thing that we should be doing is encouraging people. There's still a federal law that we need to abide by when it comes to recreational use marijuana and other drugs of that nature," Spicer said in a White House press briefing , while being careful to distinguish between use of medical and recreational marijuana.

Yet when it comes to recreational marijuana and opioid addiction, many experts say there's no definitive evidence to support an exclusive connection between them. Factors fueling the opioid crisis have been identified -- and none is related to marijuana use.

"We know why there's an opioid addiction epidemic. ... I don't think there is really debate," said Dr. Andrew Kolodny, co-director of Opioid Policy Research at Brandeis University's Heller School for Social Policy and Management.

"It's because we have overexposed the population to prescription opioids," he said. "The driver behind that increase in opioid addiction has been an overprescribing of pain medicine, overexposing the population to a highly addictive drug."