In October, Canada became just the second country in the world after Uruguay to legalize marijuana. CGTN's Dan Williams visited the Canadian province of Ontario to see what has changed since then.

The town of Smiths Falls, about an hour's drive from Ottawa, was left devastated a decade ago, when a Hershey chocolate factory closed its doors throwing more than 500 people out of work. But the town is now enjoying an unexpected resurgence and all because of cannabis. 

"All of the different plants and products that we have available, anywhere in the world started in this mom room."

The chocolate factory has been converted into the headquarters for Canopy Growth Corporation. In just a few years, thanks to the legalization of both medical and recreational cannabis use in Canada, the workforce has grown to almost one thousand.

JORDAN SINCLAIR, CANOPY GROWTH CORPORATION "They were looking for a community that would allow them to grow massive amounts of cannabis. In 2013, we really had to make the sales pitch of coming here, taking over this flagship building and using it to grow narcotics."

DAN WILLIAMS, SMITHS FALLS, CANADA "To underline just how big a business cannabis has become here in Canada, this room is known as the vault. Inside is around 120 million dollars' worth of cannabis products. That equates to around six months' worth of sales for the company."

Constellation Brands, a U.S. liquor and beer company, recently invested three-point-eight billion dollars into the company. Next year, the company hopes to sell foods and drinks spiked with the active ingredients of marijuana.

But concerns remain over the negative aspects of cannabis, with fears legalization will promote usage.

Canada's Psychiatric Association is among those stressing that cannabis can increase the risk of developing a primary psychotic disorder and compound other mental health issues such as depression.

But Canada's Centre for Addiction and mental health believes marijuana's benefits far outweigh its negatives.

ROBERT MANN, SENIOR SCIENTIST, INSTITUTE FOR MENTAL HEALTH POLICY RESEARCH "Canada's cannabis policy was not effective and was problematic in terms of not really achieving any kind of health-related goals and not really controlling cannabis use. So if we are interested in controlling the negative effects of harmful use, the tobacco model which is a public health model seems to be working better than prohibition."

The center is also focusing on other social concerns not least the impact cannabis has on driving.

Akwasi Owusu-Bempah is an assistant professor in the Department of Sociology at the University of Toronto. He believes that whatever the concern over cannabis, the existing laws simply weren't working.

AKWASI OWUSU-BEMPAH, ASSISTANT PROFESSOR, UNIVERSITY OF TORONTO "It has devastating health impacts because people are being criminalized for some serious problems that they might have, instead of helping them with the issues that led them to their drug use, we are criminalizing them which makes them worse off."

Canada became just the second country to legalize cannabis after Uruguay. It is estimated the market is worth around five billion US dollars. Like a giant social experiment, the world will be watching the impact of Canada's decision very closely.

Dan Williams, CGTN Smiths Falls, Canada.