Dr. Maddison graduated from the University of Sydney in 1978. She completed an internship at the University of Sydney in 1979, spent 18 months in full time private practice then completed a residency in small animal medicine at the University of Guelph, Canada. She returned to Australia and completed a PhD on the neurochemistry of Hepatic Encephalopathy at The University of Sydney. She was a senior tutor and clinician in the Department of Veterinary Clinical Sciences from 1987 and from 1990-2000 was a senior lecturer in the Department of Pharmacology. During this time she also worked in general and specialist veterinary practice and was a consultant for a veterinary clinical pathology lab. In 2000 she became the Director of the Veterinary Science Foundation at the University of Sydney.