Aja joined the Department of Psychology, University of Edinburgh as a Lecturer in Psychology with Quantitative Focus in 2018. Her research focuses on developmental aspects of mental health, especially ADHD, internalising problems, externalising problems, and their co-occurrence. A second area of focus is on quantitative methodology, especially longitudinal methodology and psychometrics. She currently leads projects on student mental health, domestic violence during pregnancy, and survey methodology and am the deputy director of the Evidence for Better Lives Study.

Prior to joining the department, she was a Research Fellow at Emmanuel College, University of Cambridge where she researched  developmental trajectories of mental health issues and their co-occurrence. She also previously worked as a Research Associate in the Violence Research Centre at the University of Cambridge. There she worked on developmental trajectories of ADHD symptoms and conduct problems in the Zurich Project on Social Development from Childhood to Adulthood (z-proso) and later on the Evidence for Better Lives Study.