Recovery Outcomes and Temporal Correlates in Individuals with Polysubstance Use

Abstract

Polysubstance use disorder (polySUD) presents a significant challenge in the field of addicition due to its high prevalence, variability in recovery trajectories, and poorer treatment outcomes. This dissertation introduces and validates a novel construct—proportion of remission (PrR)—as a continuous measure that captures nuanced recovery progress in individuals with polySUD. Study 1 utilized data from a remote sample of 2,406 individuals with polySUD to examine the association between PrR and Quality of Life (QoL) across four domains: physical, psychological, social, and environmental. Results indicated that higher PrR was significantly associated with improved QoL in all domains, suggesting that PrR offers a granular metric for evaluating recovery outcomes. Study 2 extended this work by exploring how PrR relates to behavioral and recovery-specific variables, including delay discounting (DD), maximum time in recovery, and quit time across substances. Findings demonstrated that longer quit time and reduced discounting rates significantly predicted higher PrR, with a moderated mediation model showing that quit time mediated the relationship between recovery duration and PrR depending on DD levels. Study 3 evaluated the Proximity to Future Index (PTFI)—a non-monetary proxy for temporal window—as an alternative to DD. Results showed that PTFI and DD independently predicted recovery outcomes, including QoL and remission, highlighting the relevance of temporal cognition in recovery science. Collectively, these studies support the clinical utility of PrR as a continuous, person-centered indicator of recovery from polySUD and underscore the potential of temporal window measures like DD and PTFI in understanding and enhancing recovery trajectories.