Algorithmic hyperindividualisation and the transformation of vulnerability in substance use prevention

Generative artificial intelligence is entering substance use prevention through applications that tailor health information to the individual in real time. These systems promise to reach vulnerable groups more precisely than mass communication, and they rest on individual-level models of behaviour change. This article asks what happens to the concept of vulnerability once it becomes something such a system can read and act upon. It draws on the public health literature on vulnerability as a multilevel construct, the theory of fundamental causes, Rose's prevention paradox, and critical work on algorithmic systems and precision public health. On this basis it develops the Vulnerability Transformation Hypothesis. The article first distinguishes hyperindividualisation from the tailoring it intensifies. What is new is the inference of undeclared attributes, continuous re-profiling, open-ended generation, and operation at near-zero marginal cost per message. The hypothesis is stated as three claims of decreasing certainty. A near-analytic addressability claim holds that a system addressing users as individuals has only individual-level levers. A substantive and conditional re-encoding claim states that, for any system presenting itself as a means of reaching the vulnerable, the operationalised concept of vulnerability is reconstructed into a constellation of individual attributes. Structural information that enters an individual model returns as a predictor of personal risk rather than as a target of action. This transformation is representational rather than ontological, since the structural causes persist even as they recede from what the system can represent and change. A contingent displacement claim adds that, at the level of the field rather than the single system, the success of individualised tools may displace structural effort, a tendency documented as lifestyle drift. The article separates its claim from the precision public health debate and offers four falsifiable predictions. Among them is a discursive test of whether systems that invoke vulnerability then present individual tailoring as the means of addressing it. Such a pattern would evidence substitution of the concept, not mere inconsistency. The article illustrates the coding scheme across contrasting systems, so that others can test and revise the hypothesis.