Polysubstance Use projects can include diversity issues such as gender, age, socio-economic status sexual orientation or migration. Prevention, treatment and harm reduction can also serve as method for targeted interventions to prevent multiple substance use. Polysubstance Use projects are particularly important in the area of quality management. Even if a large proportion of the population does not consume several substances at the same time, certain combinations of medicines, cannabis and other illegal drugs, seem to affect a significant number of people according to the Swiss Addiction Monitoring. However, the health risks of substances frequently consumed together or during the same night in Swiss nightlife have been addressed and researched very sparingly. Studies on the burden or morbidity associated with multiple substance use are also lacking. There is also a lack of reliable burden figures on the combined consumption of alcohol and drugs. The ISGF has made contributions primarily in the area of diversity, to gender, migration, age and addiction, as well as sexual orientation. Figures on multiple substance use are collected by Swiss Addiction Monitoring as part of the evaluation of Safer Nightlife Swiss as well as in the Global Drug Survey in cooperation with the ISGF.