The role of interoception and alliesthesia in addiction

Abstract

This review presents a novel conceptualization of addiction, integrating the concepts of interoception (i.e., the CNS representation of visceral feelings) and alliesthesia (i.e., that rewarding properties of stimuli are dependent on the internal state of the individual) with existing theories. It is argued that the body state, as defined by the integration of interoceptive information, is a crucial arbiter of the risk for initiation of and transition to compulsive use of addictive compounds. Overall, individuals at risk for drug dependence are characterized by an altered internal bodily state that leads to a change in hedonic and incentive motivational properties of addictive drugs. Specifically, drug dependent individuals experience alliesthesia of interoceptive processing, leading to increased incentive motivational properties of the drug over time and thereby increasing the probability of subsequent use. This extension of previous theories of addiction to include interoception and alliesthesia is based upon a clearly delineated set of neural substrates mediating interoception, key elements of which also recently have been implicated in drug addiction. The model thereby provides new potential targets for interventions that are aimed at changing the internal state that puts the individual at risk for continued substance use.

Figure 1. Conceptual model of interoceptive dysregulation in addiction

This figure conceptualizes the proposed alteration in interoceptive processing in drug addiction. Drug-use itself can be seen as a repeated perturbation of the current body state, which becomes associated with conditioned stimuli that contribute to the sensitization of the body prediction error. In drug dependent individuals, the internally generated states are a result of long-term adjustments due to allostatic dysregulation, which renders the individual in an unstable and presumably aversive body state. It is proposed that addicted individuals exhibit two types of abnormalities: (1) an increase in body prediction error and insula response to anticipating and experiencing aversive events, potentially due to allostatic dysregulation; and (2) an increased decay of the body prediction error and insula activity following the experience of an aversive event, which results in a decreased flexibility to adjust behavior when anticipating or experiencing an aversive event.