Schedule of voucher delivery influences initiation of cocaine abstinence.

This study examined whether voucher delivery arrangements affect treatment outcome. First, 90 cocaine-dependent adults were randomly assigned to behavioral counseling or counseling plus vouchers for cocaine-free urine samples. The value of each voucher was low at the beginning but increased as the patient progressed (Voucher Schedule 1). Voucher Schedule 1 produced no improvements relative to counseling only. Next, 23 patients received vouchers on either Voucher Schedule 1 or Voucher Schedule 2. Voucher Schedule 2 began with high voucher values, but requirements for earning vouchers increased as the patient progressed. Average durations of cocaine abstinence were 6.9 weeks on Voucher Schedule 2 versus 2.0 weeks on Voucher Schedule 1 (p = .02). This confirms that vouchers can assist in initiating abstinence and that voucher delivery arrangements are critical.