Diagnosing mental health conditions need not be a case of yes/no

‘The concept of diagnosis may be less useful and we may all, more readily, accept each other’s differences.’ Photograph: Islandstock/Alamy

Lucy Foulkes explores the possibility that the rising numbers of young people receiving a diagnosis of mental illness or ADHD are subjects of overdiagnosis (Are we really overdiagnosing mental illness?, 22 February). She posits that changes in terminology, increasing societal awareness and reductions in stigma are all factors in the increase in diagnoses.

However, there is another way of looking at this issue. If we treat ADHD as binary (you have it or you do not), we are missing the possibility that we all lie somewhere on a continuum with diagnosed ADHD towards one end (and perhaps an ability to focus and concentrate at the other). A diagnosis of ADHD then depends on where the line is drawn. I suggest that this line has been moved in recent years, so that a large group of people have been caught up in the positive ADHD group, who would not have been previously.