Depression scales may not work the same for highly intelligent people

"The data revealed the curved relation the researchers were expecting: the highest intelligence levels seemed to be associated with declines in mental health. But then the scientists found a problem. To make sure their results were valid, they ran statistics tests to determine whether the mental health measures work the same for people at different intelligence levels, in part by calculating whether responses to individual questions reflect depression to the same extent for everybody."

"Both scales failed this test, meaning they can't be used to compare people with differing intelligenceand conclusions like this study's can't be trusted. The finding casts doubt on previous studies that used these tools without accounting for intelligence and suggests depression screening in doctor's offices may be flawed."

"They hypothesized that the association between intelligence and better mental health starts out positive as it approaches the high end of the IQ scale, then turns negative. The researchers analyzed data from two U.S. surveys that tracked thousands of people over decades. To estimate IQ, these surveys used an aptitude test that measures math and language abilities. Each used a different well-established mental health scale containing questions about things such as mood, sleep and appetite."

"To make sure their results were valid, they ran statistics tests to determine whether the mental health measures work the same for people at different intelligence levels, in part by calculating whether responses to individual questions reflect depression to the same extent for everybody. Both scales failed this test, meaning they can't be used to compare people with differing intelligenceand conclusions like this study's can't be trusted."

Two widely used depression questionnaires do not work for comparing people with different intelligence levels. A study examined how intelligence relates to mental health using data from two large U.S. surveys spanning decades. Intelligence was estimated with aptitude tests measuring math and language abilities. Mental health was assessed with established scales covering mood, sleep, and appetite. Results showed a curved relationship where mental health appeared to improve toward higher IQ and then decline at the highest IQ levels. Statistical checks tested whether the questionnaires functioned the same way across intelligence groups by evaluating whether individual items reflected depression similarly for everyone. Both scales failed these checks, so they cannot support valid comparisons across intelligence levels. This raises concerns about prior research and about depression screening in clinical settings.

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