Over the past 25 years, Dr. Mellins has completed projects examining neurodevelopment, mental health, and sexual and drug risk behavior in vulnerable population of children, adolescents, and young adults, particularly those affected by HIV, poverty and substance abuse. Her projects have also examined factors influencing medical adherence, sexual and drug risk behavior, and psychiatric functioning in HIV-infected and HIV-affected children, adolescents, and young adults. She has been the Principal Investigator or Co-Investigator of a large number of foundation and federally-funded research projects based in the US and internationally, including multiple cohort studies of perinatally HIV-infected and perinatally HIV-exposed children and adolescents.