Machine learning of neural representations of emotion identifies suicidal youth

&quot;This study used machine-learning algorithms (Gaussian Naive Bayes) to identify such individuals (17 suicidal ideators versus 17 controls) with high (91%) accuracy, based on their altered functional magnetic resonance imaging neural signatures of death-related and life-related concepts.&quot;<p>Anyone with a Nature subscription want to check whether they simply trained their discriminator and then used it on the same data set? There&#x27;s no mention in the abstract of testing it against a fresh control set and that&#x27;s not promising.<p><a href="https:&#x2F;&#x2F;www.nature.com&#x2F;articles&#x2F;s41562-017-0234-y?error=cookies_not_supported&amp;code=6e85e088-d042-4f52-a19e-320e2cd0bdd0" rel="nofollow">https:&#x2F;&#x2F;www.nature.com&#x2F;articles&#x2F;s41562-017-0234-y?error=cook...</a>

Doesn&#x27;t 91% seem far too low to be useful for the general population? Consider that only 7% of the background population experiences one or more depressive episode per year[0] (edit: okay maybe 8% in youth). Assuming independence and using the higher 8% background rate figure for youth, .91 * .08 = 7.3% of the population will receive a true positive result and (1-.91) * (1-.08) = 8.3% of the population will receive a false positive result. This is &quot;pretty bad&quot; — false positives outweigh the true positives — making the value of a positive result useless.<p>(Consider what happens to people so-diagnosed as suicidal when in fact they are not (false positives). Involuntary psychiatric imprisonment is a terrible thing if it isn&#x27;t absolutely necessary.)<p>[0]: <a href="https:&#x2F;&#x2F;www.healthline.com&#x2F;health&#x2F;depression&#x2F;facts-statistics-infographic" rel="nofollow">https:&#x2F;&#x2F;www.healthline.com&#x2F;health&#x2F;depression&#x2F;facts-statistic...</a>

Will it be that 10% of people are suicidal and it always predicts non-suicidal?<p>Will it be that accuracy actually means AUC?<p>Will it be that they are reporting predictive skill on the training data?

&quot;Words like death and cruelty differentially activated the left superior medial frontal area and the medial frontal&#x2F;anterior cingulate in the individuals with suicidal ideation – these are areas associated with self-referential thought.&quot; I wonder how they reacted to &quot;alive&quot; and &quot;humane&quot;

It&#x27;s the kind of &quot;studies&quot; you call BS on first, then go on to figure out the details. Not a very scientific process for sure, but always produces the correct result.<p><a href="https:&#x2F;&#x2F;www.naturalblaze.com&#x2F;2017&#x2F;03&#x2F;scandal-mri-brain-imaging-completely-unreliable.html" rel="nofollow">https:&#x2F;&#x2F;www.naturalblaze.com&#x2F;2017&#x2F;03&#x2F;scandal-mri-brain-imagi...</a>

Slightly off topic but the book &quot;Change your brain change your life&quot; was pretty interesting. Perhaps not as scientific as some would prefer, but none the less thought provoking.

Basically you extract a matrix representation of the active or inactive regions that is classified and have DNN learn it like you would learn images, is that a correct assumption?

To the moderators, the title would be more accurate with &#x27;fMRI&#x27; as opposed to &#x27;MRI&#x27;. The latter is typically used to examine structural brain elements, whereas fMRI is thought to correlate with brain activity and, by extension, thought.<p>Confusing the two would lead to the more unusual conclusion that suicidal ideation is associated with abnormal brain connectivity, while the authors are instead focusing on neuronal activity.

So what will they do after they detect you are suicidal? Stick you in a psych ward? Yet more attempts at taking away the rights of those going through trauma.

Maybe they should use this test before gun purchases... I don&#x27;t think someone suicidal should purchase a gun...hell I don&#x27;t care if they kill themselves, but lately a lot of suicides were mass suicides...we don&#x27;t need more of that shit.