As the debate over legalizing marijuana continues to smolder across the country, it's possible to imagine a day when different brands of pot will compete for your attention.

But it's already a reality when it comes to a drug known as "synthetic cannabis". It's sold today under such brand names as Legal Weed, Spice, and K2.

And while the packages are all labelled, "Not for Consumption".... people are most definitely consuming these products.

Smoking synthetic cannabis is becoming increasingly popular in some parts of the world — but the substance's effects can be so dangerous, and unpredictable, that New York's police commissioner has dubbed the stuff "weaponized marijuana".

The American Association of Poison Control Centers has stated that in the first 5 months of 2015 there were almost 4,000 reports of illness related to synthetic cannabis in the U.S. And 15 deaths were linked to the drug over that same period. In Canada, at least one death is being investigated for a possible link to the use of this drug.

People find it for sale in stores and especially online. And our first guests today — a couple from Edmonton — say they found themselves on a downward spiral after getting hooked on synthetic cannabis. We reached Carmen Caldwell and Martin Bercier at their home in Edmonton.

Drug and addiction specialists here in Canada are doing their best to better understand synthetic cannabis. But it's no small task. The composition of synthetic cannabis varies a great deal, making testing a challenge.

Matthew Young is a senior research and policy analyst at the Canadian Center on Substance Abuse. We reached him in Ottawa.