A researcher at Dalhousie University in Halifax is looking at how cannabis use can affect brain function in young adults.

Dr. Philip Tibbo, a professor of psychiatry, is conducting the study with researchers at Western University in London, Ont. It involves 180 people in both provinces between 18-35 who use cannabis to varying degrees.

One group taking part in the study is affected by some form of psychosis, such as schizophrenia, while the other group is unaffected by an illness. 

Tibbo said daily cannabis use, or even in some cases occasional use, has been shown to negatively impact early gains made by people diagnosed with psychosis.

He said he's looking at how cannabis can impact brain white matter — nerve fibres that connect various parts of the brain — during its final development phase in young adulthood.

It also happens to be a time when cannabis use can be quite heavy.

"This will actually give us a little bit better insight into how cannabis can affect brain structure and brain function," he said.

In this practice scan on the brain of a researcher at Dalhousie University's psychiatry department, white matter is shown outlined in blue.

Tibbo said he will look at whether abnormalities form in white matter as a result of cannabis use. Abnormalities in these connections mean your brain is not functioning at peak capacity.

"Each area of the brain doesn't work independently — it's all interacting. It's very complex. If you have more dysfunctional connections, the brain is not working the way that it should be," he said.

"If there's a particular threshold that is met, you could have symptoms of that disconnection, and part of that could be the expression of illness such as schizophrenia."

Using cutting-edge techniques to image the brain, Tibbo will also be monitoring if people within the healthy sample group have unusual experiences, or psychotic-like symptoms, after smoking cannabis.

"What I usually say clinically is if you're going to be smoking, you're doing it because it's supposed to be a pleasurable experience," he said.

"But if you're smoking pot and you're getting a bit more paranoid, or you're feeling a little bit more sketchy, well then perhaps there's some vulnerability there to have negative outcomes, and is that because of the effects of cannabis on your brain white matter?"

The research got underway last May. Subjects are being tested at the outset, after six months and after one year.

He said he hopes the study will eventually arm adolescents and young adults with more information to make informed decisions about cannabis use.

The study costs around $500,000 and is being funded through the Canadian Institutes of Health Research and Research Nova Scotia.