title: Examining Longitudinal Stimulant Use and Treatment Attendance as Parallel Outcomes in Two Contingency Management Randomized Clinical Trials.
abstract: The primary aim of this study was to examine stimulant use and longitudinal treatment attendance in one 'parallel outcomes' model in order to determine how these two outcomes are related to one another during treatment, and to quantify how the intervention impacts these two on- and off-target outcomes differently. Data came from two multi-site randomized clinical trials (RCTs) of contingency management (CM) that targeted stimulant use. We used parallel multilevel modeling to examine the impact of multiple pre-specified covariates, including selected Addiction Severity Index (ASI) scores, age and sex, in addition to CM on concurrent attendance and stimulant use in two separate analyses, i.e., one per trial. In one trial, CM was positively associated with attending treatment throughout the trial (β=0.060, p<0.05). In the second trial, CM predicted negative urinalysis ((-)UA) over the 12-week treatment period (β=0.069, p<0.05). In both trials, there was a significant, positive relationship between attendance and (-)UA submission, but in the first trial a (-)UA at both baseline and over time was related to attendance over time (r=0.117; r=0.013, respectively) and in the second trial, a (-)UA submission at baseline was associated with increased attendance over time (r=0.055). These findings indicate that stimulant use and treatment attendance over time are related but distinct outcomes that, when analyzed simultaneously, portray a more informative picture of their predictors and the separate trajectories of each. This 'indirect reinforcement' between two clinically meaningful on-target (directly reinforced behavior) and off-target (indirectly reinforced behavior) outcomes is in need of further examination in order to fully exploit the potential clinical benefits that could be realized in substance use disorder treatment trials.
authors.affiliation: Washington State University, College of Nursing; Washington State University, Program of Excellence in Addictions Research; Washington State University, Translational Addictions Research Center; Washington State University, Department of Health Policy and Administration. Electronic address: smcpherson05@wsu.edu.
authors.forename: Sterling
authors.initials: S
authors.lastname: McPherson
authors.affiliation: Washington State University, College of Nursing; Washington State University, Program of Excellence in Addictions Research; Washington State University, Translational Addictions Research Center.
authors.forename: Olivia
authors.initials: O
authors.lastname: Brooks
authors.affiliation: Washington State University, College of Nursing; Washington State University, Program of Excellence in Addictions Research; Washington State University, Translational Addictions Research Center.
authors.forename: Celestina
authors.initials: C
authors.lastname: Barbosa-Leiker
authors.affiliation: Washington State University, College of Nursing; Washington State University, Program of Excellence in Addictions Research; Washington State University, Translational Addictions Research Center.
authors.forename: Crystal
authors.initials: C
authors.lastname: Lederhos
authors.affiliation: Washington State University, Program of Excellence in Addictions Research; Washington State University, Elson S. Floyd College of Medicine.
authors.forename: Amanda
authors.initials: A
authors.lastname: Lamp
authors.affiliation: Washington State University, College of Nursing; Washington State University, Program of Excellence in Addictions Research; Washington State University, Translational Addictions Research Center; Washington State University, Department of Health Policy and Administration.
authors.forename: Sean
authors.initials: S
authors.lastname: Murphy
authors.affiliation: Washington State University, Program of Excellence in Addictions Research; Washington State University, Translational Addictions Research Center; Washington State University, Elson S. Floyd College of Medicine.
authors.forename: Matthew
authors.initials: M
authors.lastname: Layton
authors.affiliation: Washington State University, College of Nursing; Washington State University, Program of Excellence in Addictions Research; Washington State University, Translational Addictions Research Center; Washington State University, Department of Health Policy and Administration.
authors.forename: John
authors.initials: J
authors.lastname: Roll
mesh_terms: D000328:Adult; D001521:Behavior Therapy / Q000379:methods*; D000697:Central Nervous System Stimulants / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use; D008960:Models, Psychological; D009042:Motivation; D016032:Randomized Controlled Trials as Topic; D012054:Reinforcement, Psychology; D019966:Substance-Related Disorders / Q000534:rehabilitation* / Q000652:urine
chemical_list: D000697:Central Nervous System Stimulants; D008691:Methadone
keywords: Clinical trials; Contingency management; Parallel growth modeling; Stimulant use; Treatment attendance