Five studies were found using “THC” OR “cannabis” but three was excluded (unrelated). We found references through reference screening of previous articles. A Canadian e-survey related to adolescent reported an increase in cannabis use (and alcohol), contrary to other substances (Dumas et al., 2020). Adolescents were engaging in solitary substance use (49.3%), with peers via technology (31.6%) and, strikingly, even face-to-face (23.6%). A study reports an increase in sales activity levels on darknet markets (including social networks) during 2020, mainly related to cannabis products, questioning the impact of COVID-19 pandemic on this form of purchasing (Groshkova et al., 2020). A large French on-line survey conducted at the beginning of the lockdown reported an increase of cannabis use in 31% of participants. The main factor of increase in cannabis use was an intermediate/low level of education (Rolland et al., 2020).
