She has built an internationally recognised research profile over her 20 year career, focusing on understanding emerging drug use trends, especially related to the use of new and emerging psychoactive substances, drug checking or testing drugs for harm reduction, cannabis cultivation and digitally facilitated drug markets.

Monica is the Australian lead for the Global Drug Survey, the world's largest survey of people who use drugs. She has developed specific expertise in engaging with hidden populations using digital technologies. She also serves as the Executive Director of Bluelight.org, a global drug harm reduction community, and leads research activities for The Loop Australia, a charity providing drug checking services both at festivals and in the community. Monica has a long-held commitment to ensuring that her research has an impact outside academia. To that end she has provided critical evidence to various Australian coroners about further ways in which we can prevent drug-related deaths.