A cannabis researcher is calling for a cautious approach to changing cannabis laws.
A binding referendum on the matter will be held at the 2020 general election as the debate continues on whether or not we should make the controversial product legal.
Associate Professor Joseph Boden from Otago University's Department of Psychological Medicine has studied the use of cannabis among participants in a study of more than 1200 children born in Christchurch in 1977.
He told Tim Dower that he would like to see caution towards legislation, starting with increasing the age of purchase being raised to 20 years old
"We are suggesting a gradual approach similar to the UK to decriminalise cannabis first. A lot of the harm of cannabis abuse affects the younger age bracket as it can cause more harm developing their brains"
The study found that by age 35, almost 80 percent of participants had used cannabis at some point.
Data showed cannabis use was associated with educational delay, welfare dependence, increased risks of psychotic symptoms and major depression
Professor Boden says in some parts of the United States there is a full-on capitalist, free market approach to cannabis, but warns against following in their footsteps.
"We think this approach is conducive to increasing the harm associated with cannabis. The first step should be decriminalisation, rather than legalisation."
LISTEN ABOVE AS JOSEPH BODEN SPEAKS TO TIM DOWER