I have only read the text diagonally while looking for some keywords, but my 2 cents: in many cases, when a neuroscience study claims to be able to &quot;predict&quot; something, they mean &quot;var X and var Y show a strong correlation&quot;. Actual predictive power is not checked unless there is a real test set that is left out of the training phase and all that (cross-validation, etc).<p>When this article claims:<p>&gt; When data from GAD patients and healthy controls were combined, relatively low CHO <i></i>predicted<i></i> both relatively higher IQ and worry scores.<p>... it is actually saying that CHO is inversely correlated with higher IQ and worry scores.<p>(Unless, again, as noted above, they are cross-validating in a way that was not obvious to me when I checked for it.)