Refining the Allostatic Self-Efficacy Theory of Fatigue and Depression Using Causal Inference

Allostatic self-efficacy (ASE) represents a computational theory of fatigue and depression. In brief, it postulates that (i) fatigue is a feeling state triggered by a metacognitive diagnosis of loss of control over bodily states (persistently elevated interoceptive surprise); and that (ii) generalisation of low self-efficacy beliefs beyond bodily control induces depression. Here, we convert ASE theory into a structural causal model (SCM). This allows for identification of empirically testable hypotheses regarding casual relationships between variables of interest. We use conditional independence tests on questionnaire data from healthy volunteers (N=60) to identify contradictions to the proposed SCM. Moreover, we estimate two causal effects proposed by ASE theory using three different methods. Our analyses suggest that, in healthy volunteers, the data are not fully compatible with the proposed SCM. We therefore refine the SCM and present an updated version for future research. Second, we confirm the predicted negative average causal effect from metacognition of allostatic control to fatigue across all three different methods of estimation. Our study represents an initial attempt to refine and formalise ASE theory using methods from causal inference. Our results confirm key predictions from the ASE theory but also suggest revisions which require empirical verification in future studies.