Dr. Dahanayake obtained her MBBS degree with second class honours (upper division) from the Faculty of Medicine, Colombo in 2008. She was awarded the Bobby Somasunderam gold medal for best performance in the selection examination in psychiatry in 2011. She completed the MD in Psychiatry in 2014 and was board certified as a Consultant Child & Adolescent Psychiatrist in 2017.
She is the current Vice President of the Sri Lanka College of Child & Adolescent Psychiatrists and serves in the child and adolescent mental health subcommittee of the Sri Lanka College of Psychiatrists.
She is involved in capacity building activities related to the field of child and adolescent mental health in Sri Lanka.