11. A computer program product tangibly stored on a computer readable hardware storage device, the computer program product for mental state classification comprises instructions for causing a processor to: produce plural sets of training data that comprise words associated with multiple groups of individuals, with the multiple groups of individuals having different classifications of mental states that define a like number of multiple cohorts; execute a classification model on each of the sets of training data to classify a first group of individuals in relation to a second, different group of individuals, with the first and second groups of individuals being of the multiple groups of individuals, and different ones of the multiple cohorts; determine points of intersection of words between the first group and the second group of individuals; determine words in the training data that are unique to the first group of individuals to provide isolated statistically predictive terms for the first group to identify predictive features for a first cohort; and determine words in the representations of the training data that are unique to the second group of individuals to provide isolated statistically predictive terms for the second group to identify predictive features for a second one of the cohorts.
13. The product of claim 11 wherein the prediction is of suicidality risk.