Colleen S. Thomas

Delay discounting predicts postpartum relapse to cigarette smoking among pregnant women.

Delay discounting (DD), a measure of impulsivity, describes the rate at which rewards lose value as the delay to their receipt increases. Greater discounting has been associated with cigarette smoking and various other types of drug abuse in recent research. The present study examined whether DD predicts treatment outcome among cigarette smokers. More specifically, the authors examined whether baseline discounting for hypothetical monetary rewards predicted smoking status at 24 weeks postpartum among women who discontinued smoking during pregnancy. Participants were 48 pregnant women (10.5 = 4.1 weeks gestational age at study entry) who participated in a clinical trial examining the use of incentives to prevent postpartum relapse. Several sociodemographic characteristics (being younger, being less educated, and reporting a history of depression) assessed at study entry were associated with increased baseline DD, but in multivariate analyses only DD predicted smoking status at 24 weeks postpartum. Greater baseline DD was a significant predictor of smoking status at 24 weeks postpartum. DD was reassessed periodically throughout the study and did not significantly change over time among those who eventually resumed smoking or those who sustained abstinence. The results extend the association of DD with risk for substance abuse to pregnant and recently postpartum cigarette smokers and demonstrate a significant relationship between DD and treatment outcome.

Effects of voucher-based incentives on abstinence from cigarette smoking and fetal growth among pregnant women.

AIMS This study examined whether voucher-based reinforcement therapy (VBRT) contingent upon smoking abstinence during pregnancy is an effective method for decreasing maternal smoking during pregnancy and improving fetal growth. DESIGN, SETTING AND PARTICIPANTS A two-condition, parallel-groups, randomized controlled trial was conducted in a university-based research clinic. A total of 82 smokers entering prenatal care participated in the trial. INTERVENTION Participants were assigned randomly to either contingent or non-contingent voucher conditions. Vouchers exchangeable for retail items were available during pregnancy and for 12 weeks postpartum. In the contingent condition, vouchers were earned for biochemically verified smoking abstinence; in the non-contingent condition, vouchers were earned independent of smoking status. MEASUREMENTS Smoking outcomes were evaluated using urine-toxicology testing and self-report. Fetal growth outcomes were evaluated using serial ultrasound examinations performed during the third trimester. FINDINGS Contingent vouchers significantly increased point-prevalence abstinence at the end-of-pregnancy (41% versus 10%) and at the 12-week postpartum assessment (24% versus 3%). Serial ultrasound examinations indicated significantly greater growth in terms of estimated fetal weight, femur length and abdominal circumference in the contingent compared to the non-contingent conditions. CONCLUSIONS These results provide further evidence that VBRT has a substantive contribution to make to efforts to decrease maternal smoking during pregnancy and provide new evidence of positive effects on fetal health.

Changes in the relative reinforcing effects of cigarette smoking as a function of initial abstinence

RationaleExperimental research is needed in investigating how early smoking abstinence affects relapse risk.ObjectiveThe present study assessed the feasibility of promoting smoking abstinence using once- rather than thrice-daily abstinence monitoring and the relationship between different durations of initial abstinence and changes in smoking preference.MethodsParticipants were 34 adult smokers randomized into one of two conditions: 14-day (14C) and 1-day (1C) contingent payment for smoking abstinence. Smoking status and participant ratings were assessed daily; a delay discounting task involving hypothetical money and an inter-temporal choice task involving hypothetical money and cigarettes were administered at baseline and days 7 and 14; a direct test of preference for smoking versus money was assessed on day 14.ResultsOnce-daily monitoring gained robust experimental control over smoking abstinence. No differences in delay discounting for hypothetical money were observed between the two conditions. Compared to the 1C condition, participants in the 14C condition (1) showed significant increases in the mean percent of delayed hypothetical money over cigarettes choices in the inter-temporal choice task, (2) were significantly less likely to ever choose the smoking option in the direct test of preference for smoking versus money, and (3) reported greater ease of abstaining from smoking and lower nicotine withdrawal and craving.ConclusionsThese results offer a more efficient procedure for experimentally promoting smoking abstinence, while providing further evidence that an initial period of sustained abstinence produces a profile of changes consistent with an overall lowering of relapse risk.

Abstinence-Contingent Reinforcement and Engagement in Non-drug Related Activities among Illicit Drug Abusers

Methadone-maintained cocaine abusers (N = 78) were randomly assigned to 1 of the following 52-week interventions: (a) usual care only (UC), (b) take-home methadone doses contingent on cocaine- and opiate-negative results (THM), or (c) take-home methadone doses for cocaine- and opiate-negative results and monetary-based vouchers contingent on cocaine-negative urinalysis results (THM + V). Cocaine use was assessed by urinalysis on a thrice-weekly schedule. Frequency and enjoyability of non-drug-related activities were assessed with the Pleasant Events Schedule (PES) at baseline, midtreatment, and end of treatment. The THM + V condition achieved the greatest abstinence from cocaine and opiate use, followed by the THM and UC conditions. The THM + V condition had the highest PES frequency ratings at midtreatment and at the end of treatment, followed by the THM and UC conditions. There were significant differences between the THM + V and UC conditions on 10 of 12 PES-derived subscales. Analyses revealed that abstinence mediated the effects of treatment condition on frequency ratings. There were no significant differences in enjoyability ratings. These results suggest that when contingency-management interventions increase abstinence from drug abuse, they also increase engagement in non-drug-related activities in naturalistic settings.

Utility of prompting physicians for brief alcohol consumption intervention.

A comprehensive prompting strategy designed to maximize the rate of Brief Intervention (BI) for “heavy drinking” was implemented from 2001 to 2003 for a randomized controlled trial of a post-BI treatment enhancement. Thirty-one internists at four outpatient practices in a county of 150,000 in a rural US state documented their BIs using an intervention checklist. The prompting procedures implemented in this study yielded documented BI for 39% of identified cases, but participation rates varied by physician and clinic and over time. The overall rate was lower than expected. Implications and recommendations for future BI research and training are offered; the papers limitations are discussed.