A: Yes. Part of the diagnostic process is, in as much as is possible, other explanations are ruled out. Part of the diagnostic criteria required for a diagnosis of AD/HD is to rule out more salient alternative explanations i.e. other conditions being the cause of problem behaviours. Conditions to be ruled out are spelt out in the DSM-5 ADHD criteria – “The symptoms are not better explained by another mental disorder (such as a mood disorder, anxiety disorder, dissociative disorder, or a personality disorder). The symptoms do not happen only during the course of schizophrenia or another psychotic disorder”.