In my experience, with enough data you do find lots of correlations between psychiatric symptoms and "cogneuro" measures, but always r ~ 0.15-.20. maybe .3 for very general measures like RT. This leads me to believe the vast majority of small-n symptom correlations are dubious.

I realize this is just the voodoo correlation argument again, but this holds for all of the N > 200 projects I've seen. There are relationships there but they are so noisy. How anyone looks at a shotgun blast of 12-20 points with an r > 0.5 and believes it is beyond me.

And lots of reasons why other than "our measures are crap". Subjective symptom reports are crazy noisy and bias prone themselves. We don't "trust the subject" about what they see or feel, but we trust them to tell us if they are delusional or depressed or whatever.

Probably we need to pay a lot more attention to the excellent work being done in psychometrics and psychiatry on the measurement problem and be a lot more critical about what a 9 item clinical scale can actually tell us.

Anyway I'm not saying anything new here, and others are saying it better, but if you don't know.... Know yah do.

Note I'm talking about both brain measures, like peak voxel BOLD/thickness/etc AND behavior-only measures. Although I'm biased as mostly work with perceptual and/or decision making stuff. Maybe it's better for cognitive control?