Although many attempts have been made to identify ADHD using standardized psychological testing, there is no standard test or set of tests to diagnose ADHD. The diagnosis is a matter of degree and must be made by a mental health professional with experience in this area who has thoroughly assessed your child’s behavior in a variety of situations. Family and teachers or employers (in the case of teens or adults) must be involved in this process. All the elements of the evaluation are matters of opinion, expectation, and comparison. Furthermore, all the behaviors associated with ADHD are normal, to some degree, in all children at certain stages of development.

It is important to identify other possible causes for the inappropriate behavior, if they are present. Physical diseases such as some forms of epilepsy , environmental influences such as family discord, and a variety of related mental disorders or a learning disability can produce behavioral patterns similar to ADHD. Children with ADHD often have other problems, such as learning difficulties, oppositional defiant disorder , or conduct disorder . Comprehensive testing and evaluation is key to properly assessing your child.

The most detailed diagnostic criteria are found in the Diagnostic and Statistical Manual of Mental Disorders, now in its fourth edition. Because most cases of ADHD are diagnosed in childhood, diagnostic criteria are geared toward children. The American Academy of Pediatrics recommends that the following guidelines be used for diagnosis in children 6-12 years old:

Diagnosis should be initiated if a child shows signs of difficulty in:

• School
• Academic achievement
• Relationships with peers and family

During diagnosis, the following information should be gathered directly from parents, caregivers, teachers, or other school professionals:

• Assessment of symptoms of ADHD in different settings (home and school)
• Age at which symptoms started
• How much the behavior affects the child's ability to function

The healthcare professional should examine the child for:

• Other conditions that might be causing or aggravating symptoms (such as anemia , thyroid dysfunction or lead toxicity )
• Learning and language problems through standardized testing and evaluation
• Aggression
• Disruptive behavior
• Depression or anxiety
• Tourette’s Syndrome

Connors Continuous Performance Testing (CPT), a computerized attention test, is often used to help confirm the diagnosis of ADHD. Examples of standardized behavior checklists that also assist in diagnosing ADHD include:

• Achenbach Behavioral Checklist
• ADD-II Comprehensive Teacher Rating Scale (ACTeRS)
• Child Behavior Rating Scale
• Copeland Symptom Checklist for Attention Deficit Disorder
• Conners Rating Scales

For a diagnosis of ADHD to be made, symptoms must:

• Be present in two or more of the child's settings (home, school, activities)
• Have started by the time the child is seven years of age
• Make it hard to function at school, at home, and/or in social situations
• Interfere with the child's ability to function for at least six months

Occasionally, a trial of treatment is used to solidify the diagnosis, but response to treatment does not confirm a diagnosis of ADHD. A proper diagnosis is as important as it is difficult because it often commits a child to years of treatment with potent and drugs that could be abused.