I did not see this so called “therapy session” but in the US, at least, a psychiatrist, Ph.D psychologist, or some master’s level therapists are trained and licensed to diagnose mental health. This didn’t sound like a normal intake to me which would have included a whole lot of questions to Harry. ADHD takes many things into consideration: usually rating scales and consultation with others close to the person. For children, parents and teachers generally fill out a rating sheet. In my career as a school counselor, I scored and faxed so many of these to physicians at parents’ request. I always asked the teacher to write a narrative as well to give the doctor the best picture of what we saw at school. And many times we saw few or no symptoms at school but the parents did at home.
This is from CHADD, a well respected organization and clearinghouse for ADHD information :
Although there is no single medical, physical, or genetic test for ADHD, a diagnostic evaluation can be provided by a qualified mental health care professional or physician who gathers information from multiple sources. These sources include ADHD symptom checklists, standardized behavior rating scales, a detailed history of past and current functioning, and information obtained from family members or significant others who know the person well. Some practitioners will also conduct tests of cognitive ability and academic achievement in order to rule out a possible learning disability. ADHD cannot be diagnosed accurately just from brief office observations or simply by talking to the person. The person may not always exhibit the symptoms of ADHD during the office visit, and the diagnostician needs to take a thorough history of the individual’s life. A diagnosis of ADHD must include consideration of the possible presence of co-occurring conditions.
Clinical guidelines for a diagnosis of ADHD are provided by the American Psychiatric Association in the diagnostic manual Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). These established guidelines are widely used in research and clinical practice. During an evaluation, the clinician will try to determine the extent to which these symptoms currently apply to the adult and if they have been present in childhood. In making the diagnosis, adults should have at least five of the symptoms present. These symptoms can change over time, so adults may fit different presentations from when they were children.
For more information: https://chadd.org/for-adults/diagnosis-of-adhd-in-adults/
Thank you for stating this because like you I have filled out more than one rating sheet for a student's physician/therapist.
Is it possible that Harry completed one prior to the visit? Or did he have records from his school years indicating issue and concerns with attention, impulsive behavior etc..?