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. Author manuscript; available in PMC: 2023 Jul 1.
Published in final edited form as: Schizophr Res. 2022 Feb 23;245:77–89. doi: 10.1016/j.schres.2022.02.002

Figure 1. Pathways to hallucinogenesis via relative prior hyper-precision.

Figure 1.

a. Medical nosology is based on a model of pathogenesis for given signs and symptoms. In this example, scleral icterus is known to be caused by high serum bilirubin. Hyperbilirubinemia itself is likely to be caused by dysfunction in a number of organ systems--increased production of bilirubin by breakdown of red blood cells, dysfunctional processing of bilirubin by the liver, or impaired clearance of bilirubin via the gallbladder. Dysfunction in these organ systems is caused by distal etiologies, including infection, autoimmune disease, or physical obstruction. Treatment is aimed at alteration of these distal causes, and tests allow clinicians to infer the causes of the signs or symptoms observed in order to identify the most appropriate interventions. Credit to Klaas Enno Stephan for the example, b. A map of potential causal pathways to hallucinogenesis with relative prior hyper-precision as a final causal step. In this example map, prior precision may be caused by inability to appropriately decrease precision of priors (primary relative prior hyper-precision) or by decreased precision of incoming sensory evidence (secondary relative prior hyper-precision), itself an adaptive response to low signal-to-noise ratio of sensory afferents. These abnormalities may be causally related to other findings commonly observed in psychosis. Rather than being an exhaustive depiction of pathways to hallucinogenesis, this causal map is meant to illustrate how recent findings may lead to a nosological map akin to that depicted in a. Superscripts denote references relevant to findings and causal pathways depicted. 1. (Cassidy et al., 2018; Corlett et al., 2019; Powers et al., 2017; Schmack et al., 2021; Teufel et al., 2015; Zarkali et al., 2019); 2.(Javitt et al., 1999; Javitt and Freedman, 2015; Rabinowicz et al., 2000); 3. (Li et al., 2017); 4. (Mancini et al., 2020); 5. (Baba et al., 2020); 6. (Hoffman and Hampson, 2011); 7. (Jardri et al., 2016); 8. (Cassidy et al., 2018; Horga and Abi-Dargham, 2014); 9. (Thiebes et al., 2018); 10. (Kehrer et al., 2008); 11. (Hughes et al., 2020; Pak et al., 2021)