This study does not have the numbers of participants to do this analysis. Even if it did you can’t rule out that to be diagnosed with GAD you need a certain IQ or that the higher your IQ the more likely the diagnosis given the underlying condition.<p>There is an interesting reversal of this effect with schizophrenia. In order to be diagnosed with schizophrenia you have to have social or occupational dysfunction [1] (effectively not be able to care for yourself). You can be completely delusional, but if you are able to care for yourself then you are not considered to have schizophrenia. People with a high IQ you are often able to look after themselves while delusional much more effectively than people with a low IQ and so not meet the DSM criteria. The underlying biology maybe identical, but the diagnosis is different.<p>1. <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Diagnosis_of_schizophrenia" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Diagnosis_of_schizophrenia</a>