A new study led by the University of South Australia (UniSA) has found that cannabis use increased during the first Covid-19 lockdown from April to June 2020.

According to the findings, cannabis consumption increased significantly (p < 0.05) during and after the lockdown period compared to all preceding months for all states and territories except the Northern Territory.

UniSa associate professor Cobus Gerber

The study, published in Environmental Science and Technology Letters in collaboration with UniSA, the University of Queensland and the University of Adelaide, collected wastewater samples every two months from 20 treatment plants across Australia.

The samples were tested for methamphetamine (ice), MDMA (ecstasy), cocaine, cannabis and alcohol and collected between August 2016 and December 2019 and then again between February and June 2020. 

While cannabis use increased, the use of other drugs such as ice dropped more than 50% in Western Australia, with moderate and delayed drops in South Australia and Victoria. The researchers said this was most likely due to border closures disrupting supply lines of those drugs compared to cannabis, which is produced locally. 

UniSa associate professor Cobus Gerber said: “This study provides an insight into the first four months of Covid restrictions in Australia. It remains to be seen what the longer-term effect of the pandemic will be.” 

The findings are in line with research from the Australian Institute of Criminology (AIC) which found cannabis use increased among detainees during the pandemic.