Psychological Testing and Diagnosis

Reading through the Diagnostic and Statistical Manual of Mental Disorders-IV it quickly becomes apparent that most of the diagnoses that we make for a child or adolescent are not dependent upon data obtained through psychological testing. Most DSM-IV diagnoses are based on history and symptoms. The most obvious exceptions are Learning Disabilities, cognitive processing disorders and Mental Retardation. In some cases, psychological testing is not required to make a diagnosis, but it is clearly indicated. For example, most clinicians recognize psychological testing can provide valuable information when there has been trauma at birth, developmental delay, a drug overdose, head injury, surgery, regression in development, or a serious medical illness.

Given that psychological testing is not needed to make a diagnosis, why is it so common for children referred for behavioral and emotional problems to undergo psychological testing? There are a number of very good reasons. In many cases testing can assist in clarifying a diagnosis. For example, depression and anxiety share many overlapping symptoms and behaviors. A brief battery of tests can assist in clarifying what the salient issues are. Testing is not decisive when making the diagnosis, but is undertaken to clarify the nature and extent of a particular problem. Psychological tests can be used to rule out other disorders and identify strengths and weaknesses. For example, a child suspected of having a Mood Disorder may be administered an IQ test, projective testing, and may be asked to complete a variety of questionnaires. The goal of this testing would be to ensure that there are no complicating factors such as a cognitive impairment or co-morbid condition, identify factors involved in the mood disorder (e.g., body image, self-esteem, peer issues), and to assess the seriousness of the mood disorder.

In some cases guidelines promulgated by professional organizations provide strong recommendations for obtaining information that can only be gathered through psychological testing. For example, the American Academy of Pediatrics makes the following recommendation when assessing for ADHD:

“In the evaluation of a child for ADHD, the primary care clinician should include assessment for other conditions that might coexist with ADHD, including emotional or behavioral (e.g., anxiety, depressive, oppositional defiant, and conduct disorders), developmental (e.g., learning and language disorders or other neurodevelopmental disorders), and physical (e.g., tics, sleep apnea) conditions.”

As we learn more about disorders such as ADHD, Bipolar Disorder, and Asperger’s it is becoming very clear that most children with one of these diagnoses have other cognitive issues that affect their functioning. Impairments in long-term retrieval, working memory, and cognitive fluency can only be identified by psychological testing. Further, without proper assessment, appropriate accommodations and interventions cannot be identified. Children exhibiting behavior problems may have limited intellectual capacity, a learning disability, or a language delay. While a thorough Diagnostic Assessment can assist in identifying these issues, only a comprehensive psychological battery can rule out the presence of a learning disability, low intelligence, cognitive impairment, or language delay.