Contingent reinforcement of marijuana abstinence among individuals with serious mental illness: A feasibility study.

Abstract

University of VermontThe feasibility of using monetary incentives to promote abstinence from marijuana useamong individuals with serious mental illness was examined by using a within-subjectsexperimental design. Participants were 18 adults with schizophrenia or other serious mentalillness who reported regular marijuana use. During 2 baseline conditions, participantsreceived payment for submitting urine specimens independent of urinalysis results. During 3incentive conditions, participants received varying amounts of money if urinalysis resultswere negative for recent marijuana use. The number of marijuana-negative specimensobtained was significantly greater during incentive than baseline conditions. These resultsprovide evidence that marijuana use among at least some mentally ill individuals is sensitiveto contingent reinforcement and support the potential feasibility of using contingency-management interventions to reduce substance abuse among the mentally ill.Substance abuse among individuals with schizophreniaand other severe mental illness is a serious public healthproblem (Bellack & Gearon, 1998). Lifetime prevalence ofsubstance abuse among individuals with schizophrenia inthe United States is near 50% (Kessler, 1994; Mueser,Bennett, & Kushner, 1995). In the National Institute ofMental Health's Epidemiologic Catchment Area study ex-amining U.S. prevalence rates of psychiatric disorders, oddsof having a substance abuse diagnosis (not including to-bacco) were 4.6 times higher for persons with schizophreniathan for the general population (Regier et al., 1990). Mari-juana use is the most common form of illicit drug useamong individuals with schizophrenia as it is among thegeneral population (Kandel, Chen, Warner, Kessler, G Richardson, Craig, & Haugland, 1985; Zisooket al., 1992). Rates of marijuana use are even higher amongpersons with schizophrenia than those with other psychiatricdiagnoses (Negrete & Gill, 1999; Tsuang, Simpson, & Kan-frol, 1982).Substance abuse by individuals with schizophrenia isassociated with many serious adverse consequences relatedto their psychiatric illness in addition to the more commonStacey C. Sigmon, Department of Psychology, University ofVermont; Sandra Steingard and Stacey L. Anthony, Department ofPsychiatry, University of Vermont; Gary J. Badger, Department ofMedical Biostatistics, University of Vermont; Stephen T. Higgins,Departments of Psychology an d Psychiatry, University of Ver-mont.Preparation of this article was supported by Research GrantsDA06113 and DA08076 and Training Award DA07242 from theNational Institute on Drug Abuse. We thank Jennifer Dodge fortechnical assistance in preparing this article and Conrad Wong andRobert Dantona for assistance in conducting the study.Correspondence concerning this article should be addressed toStephen T. Higgins, University of Vermont, HBPL-Ira AllenSchool, 38 Fletcher Place, Burlington, Vermont 05401-1419. Elec-tronic mail may be sent to stephen.higgins@uvm.edu.adverse social and health consequences observed in others(Ananth et al., 1989; Bellack & Gearon, 1998). Substanceabuse is associated with an earlier or more abrupt onset ofpsychiatric symptomatology (Andreasson, Allebeck, R Breakey, Goodell, Lorenz, & McHugh,1974; Mueser et al., 1990) and may contribute to a poorerclinical outcome (Carpenter, Mulligan, Bader, & Meinzer,1985; Martinez-Arevalo, Calcedo-Ordonez, & Varo-Prieto,1994; Seibyl et al., 1993). As is the case more generally,substance abuse is associated with impaired general func-tioning of individuals with schizophrenia, including in-creased rates of violence (Cuffel, Shumway, Chouljian, M Fulwiler, Grossman, Forbes, & Rutha-zer, 1997; Swanson, 1993), housing instability and home-lessness (Caton et al., 1994; Drake et al., 1991), and in-creased risk for HIV infection (Carey, Carey, Weinhardt, G Kalichman, Kelly, Johnson, & Bulto, 1994;Knox, Boaz, Friedrich, & Dow, 1994). Substance abuseamong persons with schizophrenia also is associated withoverutilization of services, including high rates of hospital-ization, rehospitalization, and utilization of jail and emer-gency services (Barrels et al., 1993; Drake & Wallach,1989; Seibyl et al., 1993). As might be expected, problemswith misuse of disability benefits among individuals withcomorbid substance abuse and schizophrenia have beennoted. In the most definitive study on this topic, 105 veter-ans with schizophrenia and cocaine dependence were stud-ied (Shaner et al., 1995). Cocaine use, psychiatric symp-toms, an hospita l admissions al peake during the 1stweek of the month, shortly following receipt of disabilitypayments.There have been increased efforts to develop effectivesubstance abuse treatments for this population (Bellack &Gearon, 1998). However, there are few controlled studiesexamining the efficacy of these treatments. The most thor-oughly researched of these interventions is the integratedapproach (Drake, Mercer-McFadden, Mueser, McHugo, &Bond, 1998). Integrated substance abuse treatment is a509