Long-term Behavior Change - 1

Behavior Change: Reinforcement Schedule Effects

The purpose of this study is to determine if different reinforcement procedures (i.e., schedules) produce different patterns of long-term abstinence from methamphetamine. We anticipate that the three contingency management conditions will promote longer periods of abstinence in the year following treatment relative to the standard control group. Furthermore, we predict that the intermittent reinforcement procedures will produce longer periods of continued abstinence (i.e., long-term behavior change) in the year following treatment than the continuous reinforcement procedure. Finally, we predict that the intermittent unpredictable schedule will produce longer lasting behavior change than the intermittent predictable schedule. Methamphetamine use will be measured using urine toxicology and self-report of methamphetamine use.

Briefly the four study conditions are: (1) standard treatment which consists of 16 weeks of psychosocial treatment, (2) continuous contingency management which consists of 16 weeks of psychosocial treatment with a contingency management procedure in effect during the first twelve weeks in which vouchers are made available after each provision of a methamphetamine-negative urine test, (3) intermittent predictable contingency management which consists of 16 weeks of psychosocial treatment with a contingency management procedure in effect during the first twelve weeks in which vouchers are available after the provision of every three consecutive methamphetamine-negative urine samples, and (4) intermittent unpredictable contingency management which consists of 16 weeks of psychosocial treatment with a contingency management procedure in effect during the first twelve weeks in which vouchers are available on one day each week (randomly selected after the first week) for the provision of methamphetamine-negative urine samples provided all urine samples since delivery of the last reinforcer were also methamphetamine negative.

Inclusion Criteria:

• Meet Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for methamphetamine dependence
• Willing and able to comply with study procedures
• Willing and able to provide written informed consent

Exclusion Criteria:

• Have a medical condition that, in the study Principal Investigator (PI's) judgment, might interfere with safe study participation
• Have a recent (past 30 days) history of suicide attempts and/or current serious suicidal intention or plan as assessed by the Beck Depression Inventory (BDI)
• Have a history of violent criminal behavior or be on parole
• Any other circumstances that, in the opinion of the PI, would interfere with safe study participation