The Assessment and Diagnosis of ADHD


The assessment and potential diagnosis of ADHD is not an easy fifteen-minute doctor’s visit. The process should be thorough and take more than one visit. The process is one of evaluating symptoms and defining their inclusion into the typical ADHD symptom profile, while at the same time excluding any other possible reason or medical condition for these symptoms to occur. A thorough assessment by the physician should include a complete medical history and physical (the physical may be done by a family physician prior to the assessment). A screening to rule out any possible physical disorders such as, hyper or hypo thyroid disorder, kidney or liver disorders and epilepsy should also take place. If not recently done, a general hearing and vision test should take place to ensure hearing or vision is not compromised.

In addition, the assessment should include a psychiatric medical history of the child and family and an extensive interview with the parents to discuss the child’s strengths and difficulties. A discussion with the child, if they are old enough, should also take place at this time. In addition, various symptom rating scales should be filled out by both parents (especially if the child is living in more than one home) and the teacher. Generally more than one type of scale is used to confirm results.

During a complete diagnostic procedure, a screening for other mental health conditions that often coexist with ADHD should be completed. Only one in five people have uncomplicated ADHD, or ADHD without any other co-existing conditions. Some of the conditions that we routinely see with ADHD are: learning disabilities (LDs), anxiety, depression, and oppositional defiant disorder (ODD). On the flip side, ADHD can also be a co-existing disorder of (or often seen with) many other disorders such as Tic Spectrum Disorders, Bipolar Disorder, Conduct Disorder, Intellectual Disabilities, Mood Disorders and  Autistic Spectrum Disorder. For this reason it is very important to have a thorough assessment to review all symptoms and “red flag” of any and all potential disorders. Unfortunately, some coexisting conditions do not fully present until a child is older, making them difficult to diagnose at an early age. At the same time, the longer ADHD goes undiagnosed and untreated and the longer it persists into adolescence without treatment, the more likely co-existing conditions such as anxiety depression and substance abuse will occur.


If warranted by the symptom profile, specialized vision and hearing assessments can also be done. Vision tests that look at perceptual problems and not just the function of seeing can be done if the child is having significant difficulty with reading. A central auditory processing (CAP) assessment should be done to determine if the child or adolescent is processing or understands what they are hearing if typical CAP Disorder symptoms are present. CAP disorder can be misdiagnosed as ADHD, but can also occur with ADHD. Testing for CAP disorder is done by a specially trained audiologist. Eyesight and hearing tests should always proceed psychoeducational testing.

Psychoeducational testing should also occur for children who are struggling academically to assess whether any coexisting learning disabilities (LDs) may exist along with ADHD. Students with unrecognized LDs who are being treated for existing ADHD will continue to struggle at school unless their LDs are identified and resources put in place. It is also important to remember that behavioural issues, or a reluctance to do school work, may actually be a “red flag” that LDs or ADHD exist. Therefore, a complete assessment of a child’s learning strengths and needs is essential for a student who continues to be impaired at school.


Psychoeducational assessments are done by a psychologist. Before choosing a psychologist to do the tests ask these questions. Is the psychologist currently accredited and officially registered to make a diagnosis? Are they experts in the field of ADHD as well as learning disabilities? Are they prepared to produce a detailed report outlining all areas of difficulty and strength without clustering all findings into an ADHD diagnosis? Will they also be testing for; weaknesses and strengths in executive functioning; processing; language expression, especially written output; sequencing; graphomotor functioning; active working memory, as well as long and short term memory? These are all areas in which children with ADHD may be impaired and if so, should be documented outside of an ADHD diagnosis. If a student demonstrates learning impairments, due to ADHD ad /or LDs and is struggling academically, they should have the right to special education resources and accommodations.



For a diagnosis to be made symptoms need to be seen in more than one setting, such as at school and at home. This is required because symptoms may be caused by conditions in a particular environment, rather than being due to a medical condition. To qualify for a diagnosis, symptoms are required to be present before the age of twelve and at a level that impairs the child’s daily functioning.

It is not uncommon for a diagnosis of ADHD to be overlooked on the first or even second assessment if the symptoms are mild, or do not present in a typical manner. If the child if not visibly hyperactive or displaying other symptoms that parents and teachers find annoying, symptoms of inattention can often be missed. This is quite common in girls, but also in males with the primarily inattentive presentation of ADHD. In addition, if symptoms are less severe and parents are unconsciously intervening with extensive coping strategies, ADHD may not be detected until later in the child’s life.

Children with ADHD who are very bright can often cope at school by relying on their sheer intelligence, however, not only does their ADHD go undiagnosed, frequently their giftedness goes undetected as well. These children can end up feeling extremely frustrated and bored, and rarely live up to their academic potential. They may be able to make it through elementary and possibly even high school without too much trouble, but when good executive functioning skills, such as working memory, time management and organization are required at the post-secondary level, many struggle and fail without the proper assistance.


Who Can and Should Diagnose ADHD? 

An assessment may be done by a child and adolescent psychiatrist, (developmental) paediatrician, psychologist, neurologist or a family doctor who is trained in ADHD. In most cases, more than one professional will be required to complete a thorough assessment. Only physicians, not psychologists, may prescribe medication treatment. However, psychologists and other mental health professionals may be the ones to turn to for psychological and psychosocial therapy. Since making a diagnosis is not a simple procedure, it is recommended that all professionals working with your child have specialized training and experience in the field of ADHD.