Cannabis is the most widely consumed illicit substance worldwide, and seems to be of particular interest to younger populations. To describe the socio-familial factors associated with cannabis abuse and to evaluate the types of substances associated with cannabis. This is a retrospective, descriptive, monocentric study of cannabis-using patients over a 3-year period. Data processing was carried out using Microsoft Office Word and Excel 2016. Among 551 hospitalized patients, 137 had used cannabis, and 88 were selected. The mean age was 24.43 years, and the majority were male (96.6%), 93.2% of whom smoked in groups. Single people (80.7%), young people from single-parent families (63.6%) and forced labourers (56.8%) were most interested in smoking. Group influence (62.5%) dominated the reason for use. The most frequently observed associated substances were alcohol and tobacco (44.3%). Cannabis use is a real public health problem in Antsiranana, and indeed in Madagascar.