Substance-related Disorders
Conditions
Keywords
Drug Abuse, Contingency management, Voucher-based Reinforcement Therapy, Homosexuality, Homeless Persons
Brief summary
This study evaluates a contingency management program that rewards homeless, non-treatment-seeking substance abusing men who have sex with men (MSM) for abstaining from drugs and for performing prosocial behaviors. If this program motivates these individuals to increase prosocial and healthy behaviors and decrease drug/alcohol use, established prevention programs may modify their approaches to include contingency management, and use it to address the staggering public health problems homeless substance-abusing MSMs face on a daily basis.
Detailed description
Homelessness is a significant problem plaguing American cities and homeless substance abusers face increased risks. Homeless, substance abusing men who have sex with men (MSM) suffer 80% HIV seroprevalence, engage in the sex trades and resist treatment for substance abuse. For almost 30 years, the Van Ness Recovery House (VNRH) has been providing treatment services to homeless substance-abusing MSMs in Hollywood, CA. In 1994, VNRH began providing community-based HIV prevention services to non-treatment seeking homeless substance-abusing MSMs through the VNPD, its prevention division. Contingency management interventions providing positive incentives for behavior change may be particularly well suited for this disenfranchised, high-risk cohort. Specifically, voucher-based incentive therapies (VBRT) may be particularly effective since they have established potency for increasing prosocial behaviors that successfully compete with taking drugs and for reducing drug use. A randomized, controlled trial will assign 144 non-treatment seeking homeless substance-abusing MSMs at VNPD to either VBRT or control groups (72/group) for 24 weeks, with planned follow up at 7, 9 and 12 months from randomization. The VBRT group will earn vouchers in exchange for completing prosocial and healthy behaviors and/or submitting drug-negative urine and alcohol-negative breath samples. Vouchers will be redeemable for goods located in an onsite voucher store. The control group will receive feedback regarding behaviors performed and urinalysis and breath alcohol tests, but will not receive voucher points for these behaviors. We will assess the efficacy of the VBRT intervention for increasing prosocial and healthy behavior and reducing substance abuse among these non-treatment seeking homeless substance-abusing MSMs receiving services at VNPD. We will also assess the impact of VBRT on other measures of therapeutic change consistent with a harm reduction approach, including reduction of psychiatric symptoms, decreased injection drug use and high-risk sexual behavior, increased participation in prevention programming, improvement in different domains of overall functioning (medical/social/vocational), and increased readiness to change. Additionally, we will examine whether baseline participant characteristics predict VBRT outcomes. Applying VBRT to non-treatment seeking homeless substance-abusing MSMs as well as integrating VBRT into a well-established prevention program with a harm reduction philosophy are both highly innovative. Our reinforcement contingencies will also shape behavioral steps towards more complex behaviors, employing a basic operant tenet that has not received sufficient attention. Overall, our proposed research has the potential to have a significant impact on the public health of the Los Angeles homeless, gay and bisexual community. If VBRT is efficacious for motivating non-treatment seeking homeless substance-abusing MSMs in a community-based prevention program to increase prosocial and healthy behaviors and decrease drug/alcohol use, established prevention programs may modify their approaches to include contingency management, and use it to address the staggering public health problems HGMSAs face on a daily basis.
Interventions
BEHAVIORALVoucher-Based Reinforcement Therapy
Participants were randomized into either the CM or control condition. Both conditions earned points for attendance and participation (max 364 points). Participants in the CM condition also earned points for targeted health-promoting behaviors and for drug/alcohol abstinence. CM points for targeted health-promoting behaviors were not limited. Points for abstaining from substance use were awarded based on a Level 1 (recent abstinence for amphetamine, methamphetamine, PCP, and cocaine metabolites, as well as blood alcohol \<0.05) urine sample.
Sponsors
National Institute on Drug Abuse (NIDA)
Friends Research Institute, Inc.
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
MALE
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Self-identified, non-treatment seeking, men who have sex with men (MSM) at least 18 years of age and eligible to participate in the VNPD Men's Program. To be eligible to participate in the VNPD Men's Program, a person must report that they have sex with men (or men and women) and actively use drugs or alcohol. * DSM-IV diagnosis of substance dependence as determined by structured clinical interview for DSM-IV (SCID) on at least one of the following substances: alcohol, marijuana, methamphetamine, cocaine, crack, MDMA (ecstasy), opiates, or dissociative anesthetics (PCP, ketamine). These substances were chosen because they are the ones commonly used by individuals contacted by the VNPD's street outreach workers. * Ability to understand and provide written informed consent. Also see section D6.1 for consent procedures used with vulnerable populations. * Able to provide sufficient locator information for follow-up and/or known to VNPD outreach workers.
Exclusion criteria
Psychiatric health issues requiring a higher level of care.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Amount ($) Earned for Targeted Prosocial and Healthy Behaviors | 24 Weeks | Participants earned contingency management vouchers for targeted prosocial and healthy behaviors. 1 voucher = $1 |
| Proportion of Level 1 (i.e., Drug Negative Urines and Alcohol Negative Breath) Clean Urine Samples Provided at 12-month Follow-up, by Condition. | 24 Weeks | — |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Self-reported Psychiatric Symptoms at 12-month Follow-up. | 12 months | As measured by the General Severity Index (GSI), a summary domain included on the Brief Symptom Inventory. The GSI combines information on both the number of symptoms described and the severity of those symptoms. Lower values on the GSI indicate less severe symptoms. Normative non-patient populations have been shown to have average GSI scores with a mean of 0.30 and a standard deviation of 0.31. Normative outpatient psychiatric patients have demonstrated GSI scores with a mean of 1.32 with a standard deviation of 0.72. |
| Self-reported Sexual Behaviors at 12-month Follow-up | 12 months | Count of recent (past 30 days) male sexual partners. |
Countries
United States
Participant flow
Recruitment details
Recruitment occurred from April 2005 through Feb 2008 via flyers posted throughout the community, and word of mouth.
Participants by arm
| Arm | Count |
|---|---|
| Control Control condition receiving minimal incentives for service program attendance and participation. | 67 |
| Contingency Management Contingency management (Voucher-Based Reinforcement Therapy) intervention providing positive reinforcement for service program participation and attendance, enactment of prosocial/health behavior, and/or clean urine samples (i.e., no illicit drug use) and clean breathalyzer tests (i.e., BA \< 0.05). | 64 |
| Total | 131 |
Baseline characteristics
| Characteristic | Contingency Management | Control | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 64 Participants | 67 Participants | 131 Participants |
| Age Continuous | 36.3 years STANDARD_DEVIATION 8.7 | 36.5 years STANDARD_DEVIATION 8.7 | 36.4 years STANDARD_DEVIATION 8.7 |
| Region of Enrollment United States | 64 participants | 67 participants | 131 participants |
| Sex: Female, Male Female | 0 Participants | 0 Participants | 0 Participants |
| Sex: Female, Male Male | 64 Participants | 67 Participants | 131 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 67 | 0 / 64 |
| serious Total, serious adverse events | 2 / 67 | 1 / 64 |
Outcome results
Primary
Amount ($) Earned for Targeted Prosocial and Healthy Behaviors
Participants earned contingency management vouchers for targeted prosocial and healthy behaviors. 1 voucher = $1
Time frame: 24 Weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Contingency Management | Amount ($) Earned for Targeted Prosocial and Healthy Behaviors | 16.21 $ Vouchers | Standard Deviation 11.85 |
Primary
Proportion of Level 1 (i.e., Drug Negative Urines and Alcohol Negative Breath) Clean Urine Samples Provided at 12-month Follow-up, by Condition.
Time frame: 24 Weeks
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Control | Proportion of Level 1 (i.e., Drug Negative Urines and Alcohol Negative Breath) Clean Urine Samples Provided at 12-month Follow-up, by Condition. | 0.36 Proportion of Lvl 1 Clean Urine Samples |
| Contingency Management | Proportion of Level 1 (i.e., Drug Negative Urines and Alcohol Negative Breath) Clean Urine Samples Provided at 12-month Follow-up, by Condition. | 0.61 Proportion of Lvl 1 Clean Urine Samples |
Secondary
Self-reported Psychiatric Symptoms at 12-month Follow-up.
As measured by the General Severity Index (GSI), a summary domain included on the Brief Symptom Inventory. The GSI combines information on both the number of symptoms described and the severity of those symptoms. Lower values on the GSI indicate less severe symptoms. Normative non-patient populations have been shown to have average GSI scores with a mean of 0.30 and a standard deviation of 0.31. Normative outpatient psychiatric patients have demonstrated GSI scores with a mean of 1.32 with a standard deviation of 0.72.
Time frame: 12 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Control | Self-reported Psychiatric Symptoms at 12-month Follow-up. | 1.01 Units of General Severity Index | Standard Deviation 0.78 |
| Contingency Management | Self-reported Psychiatric Symptoms at 12-month Follow-up. | 0.60 Units of General Severity Index | Standard Deviation 0.62 |
Secondary
Self-reported Sexual Behaviors at 12-month Follow-up
Count of recent (past 30 days) male sexual partners.
Time frame: 12 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Control | Self-reported Sexual Behaviors at 12-month Follow-up | 3.33 Sexual Partners | Standard Deviation 9.7 |
| Contingency Management | Self-reported Sexual Behaviors at 12-month Follow-up | 0.70 Sexual Partners | Standard Deviation 1.1 |