Please explain what SWAN is, and where it comes from/background

WAN measures the Strengths and Weakness of ADHD symptoms and Normal behaviour (SWAN). It is based on The Diagnostic and Statistical Manual of Mental Disorders (DSM), which is the product of years of effort by hundreds of international experts in all aspects of mental health.

More on SWAN here https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4618695/pdf/nihms461025.pdf