“We have demonstrated that the validity of psychological tests is comparable to the validity of medical tests” –Meyer et al.
How accurate are psychological tests? Are they accurate enough to use in diagnosis? Sometimes psychological tests don’t seem as accurate because they don’t feel the same as a blood test or a brain scan. However, a thought-provoking study evaluated the accuracy of psychological tests in comparison to common medical tests.
Psychological Assessment Validity
A group of researchers, led by Gregory Meyer, gathered data from more than 125 pieces of research that looked at the accuracy of different psychological and medical tests. Each test was evaluated by the relationship between the test and the disease or disorder that test is trying to measure. For example, you could evaluate the relationship between a positive mammogram finding and actual instances of breast cancer. Although mammograms are intended to accurately find breast cancer every time, they don’t always succeed. The more often the mammogram is successful, the greater the tests accuracy.
Tests I Use IN My Psychological Assessments
I was interested to see the strength of some of the psychological tests I use in my practice and how they measured up to familiar medical tests. The MMPI is a common personality test that I often use to help with diagnosis of different psychological disorders like depression, anxiety, schizophrenia etc. This test was more accurate than a home pregnancy test.
Another common test that I use is the WAIS, which is an IQ test for adults. I often give this test to adults who are wondering if they have a learning disorder or perhaps as part of an adult ADHD assessment. It turns out that this test is about as accurate as a dental x-ray looking for cavities.
I sometimes use neuropsychological tests, which are good for screening for issues like dementia. It turns out that these tests were more accurate in identifying dementia than using an MRI.
Importance of Accurate Diagnosis
Psychological tests are important because it is often very challenging to provide an accurate diagnosis. It is difficult because many disorders have many of the same symptoms, it can be hard to be aware of all potential symptoms, and it can be hard to figure all of this out and explain it in a short medical appointment.
One of the reasons an accurate diagnosis is important is because the medical treatments for different psychological issues can be very different. For example, ADHD can often be confused with Bipolar. Unfortunately, if you give someone with bipolar an ADHD medication, they have have a negative reaction.
The importance of these psychological tests is reinforced for me every time I make an unexpected discovery. It is surprising how many individuals are surprised to discover that they have issues with anxiety. Others may have struggled with ADHD since they were young, never knowing the cause of school, work, and relationship issues. It is not just the patients who are surprised. Even after years of seeing different issues, psychological tests can show results that surprise me and make me grateful I am not relying solely on clinical interviews.
By Dr. Syras Derksen
Meyer, G., et al., (2001). Psychological testing and psychological assessment: A review of evidence and issues. American Psychologist, 128-165.