Interoceptive Processing in Substance Use Disorders (SUDs): From the Neuroanatomy to Insights from Computational Models and Predictive Coding Frameworks.

Substance use disorders (SUDs) represent complex public health challenges characterized by a blend of genetic, cognitive, environmental, and psychosocial factors. This chapter explores the critical role of interoceptive processing - the internal sensing of physiological states - in the neurobiology and treatment of SUDs. Interoceptive dysfunctions are highlighted as central to the craving, emotional regulation, and decision-making processes that underpin addictive behaviors. The importance of the insula in sustaining drug use, particularly nicotine, underscores a broader involvement of interoceptive pathways in SUDs. Altered interoceptive processing is evident across various SUDs, where individuals demonstrate both a heightened sensitivity to drug-related cues and a diminished ability to process aversive stimuli, suggesting substantial neurobiological underpinnings that complicate treatment outcomes. Moreover, we delve into the theoretical and computational approach to understanding interoceptive processing in SUDs. This perspective utilizes a predictive coding framework, positing that the brain continuously generates and updates predictions about internal states based on sensory inputs. In SUDs, disruptions in this predictive mechanism can lead to inaccuracies in interoceptive perception, contributing significantly to the compulsive nature of drug-seeking behaviors and the challenges associated with treatment. We explore how computational models, such as Bayesian inference, provide insights into the interplay between expected and received interoceptive signals, highlighting the role of hyper-precise prior beliefs in the persistence of craving and impulsivity. This theoretical approach not only deepens our understanding of the neural and cognitive bases of addiction but also suggests novel intervention strategies. By recalibrating interoceptive predictions through targeted therapies, such as neuromodulation and mindfulness training, we can potentially restore the interoceptive accuracy, thereby offering new avenues for effective treatment of SUDs.