A: The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) defines AD/HD as a condition that is “…characterized by a persistent pattern of inattention and/or hyperactivity/impulsivity that interferes with functioning or development”. It must present with a number of the diagnostic criteria behaviours; be present before 12 years of age; present in two or more settings; interfere with functioning; and the presenting behaviours have to not be better explained by another “mental disorder”.