Duration effects in contingency management treatment of methamphetamine disorders

Abstract

The primary aim of this study was to determine whether different durations of contingency management (CM) in conjunction with psychosocial treatment produced different rates of abstinence among methamphetamine dependent individuals. Participants were randomized to one of the four 16-week treatment conditions: standard psychosocial treatment or psychosocial treatment plus one of the three durations of CM (one-month, two-month, or four-month). A total of 118 participants were randomized to the four treatment conditions. There were significant differences across treatment conditions for number of consecutive days of methamphetamine abstinence (p<0.05). These differences were in the hypothesized direction, as participants were more likely to remain abstinent through the 16-week trial as CM duration increased. A significant effect of treatment condition (p<0.05) and time (p<0.05) on abstinence over time was also found. Longer durations of CM were more effective for maintaining methamphetamine abstinence.

Conflict of interest statement

Declaration of Interest: The authors report no real or potential conflict(s) of interest, including financial, personal, or other relationships with other organizations or pharmaceutical/biomedical companies that may inappropriately impact or influence the research and interpretation of the findings.

Copyright © 2013 Elsevier Ltd. All rights reserved.

Figures

Figure 1

Flow Diagram through the Phases of the Randomized Controlled Trial Note. ST = Standard Treatment. CM = Contingency Management.

Figure 2

Longest Mean Period of Methamphetamine Abstinence across Initial 16 Weeks of Study (in days). Note. CM = Contingency Management. Bars represent 95% Confidence Intervals for each of the estimated means.

Figure 3

Percent of Negative Methamphetamine UAs across the 4-Month Treatment Period for Patients with Methamphetamine Use Disorders Receiving Standard Treatment or Standard Treatment plus One of Four CM Duration Conditions. Note. CM = Contingency Management.

Figure 4

Percent of Patients with Negative Methamphetamine UAs during the Follow-Up Period across Condition and 4-Month Treatment Completion Status Over Time. Note. CM = Contingency Management.