Effectiveness of Contingency Management in the Treatment of Crack Addiction for Individuals Living in the "Crackland" Region. A Single-blind Randomized Controlled Trial
Phase: NA
Conditions: Substance Use Disorders, Contingency Management, Addiction, Cocaine
Sponsor: Federal University of São Paulo

 
Study Protocol 
 
 
 
 
Official Tittle: Effectiveness of Contingency Management in the Treatment of Crack 
Addiction for Individuals Living in the “Crackland” Region. A Single-Blind Randomized 
Controlled Trial 
 
 
 
Identifier: NCT03345394 
 
 
 
Protocol ID: FAPESP 2017/05371-8 
 
 
 
Primary Investigator: André de Queiroz Constantino Miguel, PhD. 
Rua Baicuri 213, bairro Boaçava, São Paulo-SP. CEP 05469-030- Brasil. E-mail address: 
aqcmiguel@gmail.com (A.Q.C. Miguel) 
 
 
Sponsor: Paulista Medical School of the Federal University of São Paulo 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Sao Paulo, 5th of January 2018 

Tittle:  
Effectiveness of Contingency Management in the Treatment of Crack Addiction for 
Individuals Living in the “Crackland” Region. A Single-Blind Randomized Controlled Trial 
 
Study personal and roles: 
 
André Q.C. Miguel 
 
Principal Investigator 
 
Responsible for all study related issues 
 
 
Jair J. Mari 
Clarice S. Madruga 
Claudio J. da Silva 
Ronaldo R. Laranjeira 
Sterling 
McPherson 
Crystal L. Smith 
Michael M. McDonell 
John M. Roll 
 
 
 
 
 
Co-Investigators 
 
 
 
 
 
Study design, data management, analyses 
and interpretation of the findings 
 
Viviane Simões 
 
Project Manager 
 
 
Data management, addresses IRB issues, 
conducts randomization  
 
 
Rodolfo Yamauchi 
 
Study Coordinator 
 
 
Data collection, screening, consent  
 
 
Grant funding: 
This study was funded by the Research and Innovation grant for Prevention of Mental 
Disorders and Abuse of Alcohol and Other Drugs (Pesquisas e Inovações em Prevenção de 
Transtornos Mentais e Uso de Álcool e Outras Drogas) from the Brazilian Ministry of Health 
(TED #176/2017). Dr. Miguel received two postdoctoral fellowship grants from Fundação de 
Amparo à Pesquisa do Estado de Sao Paulo (FAPESP)- processes nº 2017-05371-8 and nº 
2017-22004-9. 
 
Background: 
 Crack cocaine use disorder (CUD) is a severe health problem in Brazil, with the country being 
reported as the biggest crack market in the world. Contingency Management (CM) is one of 
the most effective treatments for CM however its effectiveness has never been evaluated in 
Brazil.  
 
Purpose: 
 The objective of this study was to evaluate the effectiveness of incorporating CM into a public 
treatment program in Brazil. 
 
Study Design: 
Single-Blind Randomized Controlled Trail where rearchers will be blinded. 
 
 
 

Study duration:  
Study duration was from December 2017 to December 2020. Data collection occurred from 
January 2018 to March 2020.   
 
Study Centers:  
This study was conducted by a partnership between the Federal University of Sao Paulo and 
the Program of excellence in Addiction Research Program from Washington State University. 
All stages of the screening, intervention and data collection processes were conducted at 
Unidade Recomeço Helvétia, a public ambulatory treatment program for CUD located in 
downtown Sao Paulo, Brazil.  
 
Objectives: Primary objective was to evaluate the effectiveness of incorporating CM into a 
public ambulatory treatment program for CUD in São Paulo, Brazil in promoting crack cocaine 
abstinence for treatment seeking individuals with CUD. The secondary objective of this study 
was to determine the feasibility and acceptability of incorporating CM into a public ambulatory 
treatment program for CUD in São Paulo, Brazil. 
 
Power: Sample size calculations were conducted according to the following parameters: 
significance level (α = 0.05), power (1 – β = 0.8), χ² test (contingency table under degrees of 
freedom = 1), and effect size (w = 0.3). These parameters resulted in a necessary sample size 
of at least 88 subjects.  
 
Randomization: 
Randomization was carried out using permuted blocks randomization with the inclusion of 
gender and baseline urinalysis result covariates for stratification to balance group-samples.   
 
 
Inclusion Criteria:  
The inclusion criteria was as follows: 1) being 18 years old or older; 2) having a current 
diagnosis of moderate to severe CUD according to The Diagnostic and Statistical Manual of 
Mental Disorders, 5th Edition (DSM-V); and 3) consenting to participate in the study. There 
were no exclusion criteria. 
 
Recruitment: 
Individuals with CUD seeking treatment at URH will be screened for eligibility.  
 
Sample size: A total of 111 subjects were screened and 98 enrolled in the study. Of these 98 
subjects, 48 subjects were randomized to the control condition and 50 subjects to the were 
randomized to the experimental condition. 
 
Intervention:  
After randomization participants will receive 12 weeks of treatment in either the control 
condition or the experimental condition.  
 
Control condition:  
Participants allocated to the control condition will receive the standard treatment provided by 
URH. The URH is an open-doors facility that provides a variety of interventions, ranging from 
harm reduction to abstinence-based interventions for crack users in different stages of recovery. 
URH offers access to showers, toilets, a beauty salon, and a gym. It also provides several group 

activities, such as self-help group counseling as well as footcare, percussion, clown, and 
experimental kitchen classes. 
 
Experimental condition: 
Participants allocated to the control condition will receive the standard treatment provided by 
URH in association with CM.  The CM intervention will consist in providing vouchers with 
monetary value contingent to the submission of a negative cocaine urinalysis (UA).  
The value of the vouchers will start at ≅ US$2.00 (as of December 2020, one US dollar was 
approximately five Brazilian reals) for the first negative UA submitted. Vouchers will increase 
by ≅ US$1.00 for every consecutive negative cocaine UA submitted up to a maximum of ≅ 
US$5.00. In addition, a ≅ US$5.00 bonus will be given if both weekly UAs test negative for 
cocaine. Participants who failed to submit a negative UA will not receive any vouchers that 
day and the value of future vouchers will reset to ≅ US$2.00.  If abstinent for the entire 12 
weeks of treatment participants can earn up to ≅ US$185.00 in vouchers. 
To reduce screening costs and reinforce acknowledgment of recent use, participants will be 
asked prior to submitting the UA if they have used cocaine in the last four days. Participants 
will be encouraged to submit the UA if they state that they have been abstinent but will not be 
required to submit a sample if they disclose recent crack cocaine use. Instead, they will be 
congratulated for admitting recent use (UA will be coded as positive by research staff) and will 
receive a token with ≅ US$0.50 value. This token may be added to a future voucher’s value, 
contingent upon the submission of a future negative UA. This procedure, we term CM Banking, 
intends to reduce costs related to screening and increase attendance among participants 
struggling to achieve abstinence. Vouchers may be exchanged for any type of goods available 
in the surrounding community immediately after the submission of a negative UA (with the 
exception of alcohol and tobacco products). After deciding on a desired commodity, 
participants will inform their respective providers. The provider will then accompany the 
participant to make the purchase. 
 
Data collection: 
Data were collected at baseline and twice weekly during the 12 weeks of the intervention. 
 
Assessments: 
Assessments include a structured sociodemographic questionnaire and questions related to the 
pattern of substance use and previous treatment history. 
The following assessments were also collected: 
 
- Diagnostic and Statistical Manual- 5º edition (DSM-V) 
- Alcohol, Smoking and Substance Involvement Screening Test -ASSIST). 
- Brief Symptom Inventorry- BSI 
- Barrat Impulsivity Scale- BIS) 
- Risk Assessment Battery -RAB) 
- Abon Biopharm cocaine urine test which is capable of detecting 300ng/ml or more of 
benzoylecgonine in the urine. 
 
Primary outcome: 
Our primary outcome was objective verification of crack cocaine abstinence assessed as 
negative cocaine UAs tested twice weekly for 12 weeks.  
 
 
 

Secondary outcome:  
Treatment retention as a secondary outcome. Retention was defined as the number of weeks 
elapsed between treatment intake and dropout. 
Statistical analyses plan. 
The primary endpoint of this study will be objectively verified abstinence based on the UA 
results collected twice weekly during the 12 weeks of intervention. Secondary endpoint will be 
duration of treatment retention.  
 
 Publication and data sharing policy: 
The preparation and submittal for publication of manuscripts containing the study results shall 
be in accordance with a process determined by mutual written agreement among the study 
Sponsor and participating institutions. The publication or presentation  
 
Conflicts of interest: 
 No conflicts of interest have been reported.