Are Psychological Assessments as Accurate as Medical Tests?

“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 correct 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 standard medical tests.

Gregory Meyer led a group of researchers to collect data from more than 125 studies that look at the efficiency of various psychological and medical tests. They evaluated each test with its relationship to the disease or disorder it’s trying to contain. For example, you could examine the connection between a positive mammogram finding and the actual occurrence of breast cancer. Although mammograms intend to find breast cancer each time accurately, they don’t always succeed. The more often a mammogram is successful, the more accurate the test.

I got an interest in seeing how the strength of some of the psychological tests I use in my practice measure up to the common medical tests. I often use MMPI, a common personality test, to diagnose various psychological disorders like anxiety, depression, schizophrenia etc. This test was more accurate than a home pregnancy test.

I also use WAIS,  a common IQ test for adults. I give this test to adults wondering whether they have a learning disorder or sometimes as part of an ADHD assessment for adults. This test turns out to be as accurate as a dental x-ray looking for cavities.

At times, I use neuropsychological tests, which are suitable for screening disorders like dementia. These tests turn out to be more accurate in diagnosing dementia than using an MRI.

Psychological tests are essential because it’s usually very challenging to give an accurate diagnosis. This is because most diseases have lots of the same symptoms. Therefore, it can be hard to be aware of all the possible symptoms, and it can be hard to figure all of this out and explain it in a short medical appointment.

One of the reasons why an accurate diagnosis is essential is because medical treatments for different psychological issues are different. For instance, ADHD can easily be confused with Bipolar. Sadly, if you give someone with bipolar an ADHD medicine, they can develop an adverse reaction.

The importance of these psychological tests is reinforced for me every time I make an unexpected discovery. It’s surprising how people are shocked to find out they suffer from anxiety. Others may have struggled with ADHD since their childhood and never know the cause of school, work, and relationship problems. It’s not just the patients who are shocked. Even after seeing different issues, psychological test results can surprise me and make me thankful I’m not relying solely on clinical interviews.

By Dr. Syras Derksen
Registered Psychologist 

References
Meyer, G., et al., (2001). Psychological testing and psychological assessment: A review of evidence and issues. American Psychologist, 128-165.