Incentivizing behaviour change to improve diabetes care.

Behavioural economics refers to the study of psychological and cognitive factors that relate to decision-making processes. This field is being applied increasingly to health care settings, in which patients receive tangible reinforcers or incentives for meeting objective behavioural criteria consistent with healthy lifestyles. This article reviews the background and efficacy of reinforcement interventions in general, and then as applied to behaviours related to diabetes prevention and management. Specifically, reinforcement interventions have been applied with some notable success towards promoting greater attendance at medical appointments, enhancing weight loss efforts, augmenting exercising regimes, improving medication adherence and increasing blood glucose monitoring. Suggestions for promising areas of future research are provided, keeping in mind the controversial nature of these interventions.

Disordered gambling among racial and ethnic groups in the US: results from the national epidemiologic survey on alcohol and related conditions.

INTRODUCTION: Prior research suggests that racial minority groups in the United States are more vulnerable to develop a gambling disorder than whites. However, no national survey on gambling disorders exists that has focused on ethnic differences. METHODS: Analyses of this study were based on the National Epidemiologic Survey on Alcohol and Related Conditions, a large (N=43,093) nationally representative survey of the adult (> or =18 years of age) population residing in households during 2001-2002 period. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-Text Revision diagnoses of pathological gambling, mood, anxiety, drug use, and personality disorders were based on the Alcohol Use Disorder and Associated Disabilities Interview Schedule-DSM-IV Version. RESULTS: Prevalence rates of disordered gambling among blacks (2.2%) and Native/Asian Americans (2.3%) were higher than that of whites (1.2%). Demographic characteristics and psychiatric comorbidity differed among Hispanic, black, and white disordered gamblers. However, all racial and ethnic groups evidenced similarities with respect to symptom patterns, time course, and treatment seeking for pathological gambling. CONCLUSION: The prevalence of disordered gambling, but not its onset or course of symptoms, varies by racial and ethnic group. These varying prevalence rates may reflect, at least in part, cultural differences in gambling and its acceptability and accessibility. These data may inform the need for targeted prevention strategies for high-risk racial and ethnic groups.

Choice between variable and fixed cocaine injections in male rhesus monkeys.

RATIONALE: The schedule of drug availability may enhance choice of a drug. In non-human subjects, reinforcers are chosen more often when available under variable schedules of reinforcement relative to fixed schedules. OBJECTIVE: To determine whether variable-drug access is an important determinant of cocaine choice by manipulating the schedule, drug dose, and combination of schedule + dose. METHOD: Four male rhesus monkeys chose between cocaine doses (0.025-0.4 mg/kg/injection). In control conditions, the schedule and dose of each drug delivery were fixed. In other conditions, the reinforcement schedule (i.e., variable-ratio schedule), dose of each cocaine delivery, or both were variable on one lever while all aspects on the other lever remained fixed. RESULTS: When cocaine dose was equal on average (0.1 mg/kg/injection), 2 of 4 subjects chose cocaine associated with the variable schedule more than the fixed schedule. All subjects chose the variable dose that was equal on average to the fixed dose, and this difference was statistically significant. Three of 4 subjects chose cocaine associated with the variable combination over the fixed option (when the dose was equal on average). During dose-response determinations (when dose on the variable and fixed options were not equal), making the schedule, dose, or both variable generally did not alter cocaine's potency as a reinforcer. CONCLUSION: While many factors contribute to drug choice, unpredictable drug access is a feature that may be common in the natural environment and could play a key role in the allocation of behavior to drug alternatives by patients with substance-use disorders.

Perceptions about professionally and non-professionally trained hypoglycemia detection dogs.

AIMS: Patients with diabetes increasingly have questions about diabetes alert dogs. This study evaluated perceptions about dogs trained professionally or otherwise to detect glucose levels. METHODS: A link to a survey about glucose detecting dogs was announced on diabetes websites. RESULTS: 135 persons responded, with 63 answering about their child with diabetes. Most respondents obtained their dog from a professional trainer (n = 54) or trained it themselves (n = 51). Owners of self- and professionally-trained dogs were very positive about dogs' abilities to alert them to low and high glucose levels, while owners of dogs that learned entirely on their own (n = 15) reported lower frequencies of alerts and more missed hypoglycemic episodes, p<.01. Regardless of how dogs learned, perceptions about managing diabetes were improved during periods of dog ownership relative to times without, p<.001. Self-reported rates of diabetes-related hospitalizations, assistance from others for treating hypoglycemia, and accidents or near accidents while driving reduced during periods of dog ownership compared to periods without dogs, ps<.01. CONCLUSIONS: These data suggest potential effectiveness of and high satisfaction with glucose-detecting dogs. Clinicians can use these results to address pros and cons of dog ownership with patients who inquire about them.

A comparison of four buprenorphine dosing regimens in the treatment of opioid dependence.

OBJECTIVES: This study compared 24-, 48-, 72-, and 96-hour buprenorphine dosing regimens in opioid-dependent outpatients. METHODS: Fourteen subjects received buprenorphine in a double-blind, placebo-controlled crossover trial. Daily sublingual maintenance doses were 4 mg/70 kg (n = 5) and 8 mg/70 kg (n = 9). After a stabilization period of maintenance administration, subjects received, in a random order, four dosing regimens for five repetitions of each regimen: a maintenance dose every 24 hours, a doubled maintenance dose every 48 hours, a tripled maintenance dose every 72 hours, and a quadrupled maintenance dose every 96 hours. In the latter three dosing regimens, subjects received placebo on the interposed day(s). Study participation was contingent on opioid abstinence and daily clinic attendance. Measures of subjective opioid agonist and withdrawal effects were assessed daily. RESULTS: Relative to standard maintenance dosing, none of the higher doses induced agonist effects. Changes in indices of subjective withdrawal effects were noted as the time since the last active dose increased during intermittent dosing regimens, but the magnitude of these effects was relatively low and was comparable to those found in other alternate-day dosing studies. CONCLUSIONS: These results support the feasibility and safety of twice weekly buprenorphine dosing regimens.

Heroin addicts have higher discount rates for delayed rewards than non-drug-using controls.

Fifty-six heroin addicts and 60 age-matched controls were offered choices between monetary rewards ($11-$80) available immediately and larger rewards ($25-$85) available after delays ranging from 1 week to 6 months. Participants had a 1-in-6 chance of winning a reward that they chose on one randomly selected trial. Delay-discounting rates were estimated from the pattern of participants' choices. The discounting model of impulsiveness (Ainslie, 1975) implies that delay-discounting rates are positively correlated with impulsiveness. On average, heroin addicts' discount rates were twice those of controls (p = .004), and discount rates were positively correlated with impulsivity as measured by self-report questionnaires (p < .05). The results lend external validity to the delay-discounting rate as a measure of impulsiveness, a characteristic associated with substance abuse.

Ro 15-4513 selectively attenuates ethanol, but not sucrose, reinforced responding in a concurrent access procedure; comparison to other drugs.

The experiments described in this report used a concurrent access procedure to study ethanol reinforcement. Rats were trained to lever press for a 10% sucrose solution and a 10% ethanol/10% sucrose mixture, and both reinforcers were available on variable-interval 5-s schedules. In baseline and vehicle injection sessions, the animals distributed their responding between both solutions. When injected with the partial inverse benzodiazepine agonist Ro 15-4513 (3, 9, and 18 mg/kg), responding for the ethanol solution decreased while responding for sucrose remained intact. Ethanol injections (0.5 and 1.0 g/kg) engendered a similar profile. Chlordiazepoxide led to an increase in ethanol mix responding at 2 mg/kg and a decrease in ethanol mix responding at higher doses; no dose affected sucrose responding. Morphine (0.5-16 mg/kg) decreased responding for both the ethanol mix and sucrose solutions, more or less simultaneously. Naloxone (0.125-20 mg/kg) selectively reduced ethanol mix responding at low doses, and decreased responding for both reinforcers at high doses. In another group of animals, isocaloric alternatives were concurrently available: 10% ethanol/0.25% saccharin versus 14% sucrose. Injections of Ro 15-4513 and chloridiazepoxide produced similar results as in the first group of rats: an increase in ethanol mix responding with low dose chlordizepoxide, and a decrease in ethanol mix responding with Ro 15-4513. However, naloxone injections did not selectively affect responding for either of the reinforcers when they were isocaloric. These results are discussed in terms of ethanol's neuropharmacological actions.

Delay discounting of money and alcohol in actively using alcoholics, currently abstinent alcoholics, and controls.

RATIONALE: Impulsivity is implicated in alcohol dependence, and discounting of delayed rewards may be an objective indicator of impulsiveness. OBJECTIVES: This study evaluated delay discounting functions in alcoholics and controls. It compared discounting rates between different magnitudes ($1000 and $100) and different types (money and alcohol) of rewards. METHODS: Active alcoholics (n = 19), currently abstinent alcoholics (n = 12) and controls (n = 15) indicated preferences for immediate versus delayed rewards using a titration procedure that determined indifference points at various delays. Four conditions were presented, and the delayed rewards in the four conditions were $1000, $100, 150 bottles of an alcoholic beverage, and 15 bottles of an alcoholic beverage. RESULTS: In all three groups across all four conditions, hyperbolic discounting functions provided a good fit of the data. Linear contrasts, predicting the most rapid discounting rates in active alcoholics, intermediary rates in currently abstinent alcoholics, and the least rapid rates in controls, were significant for three of the four conditions. Alcohol was discounted more rapidly than money. CONCLUSIONS: These data provide further evidence of more rapid discounting of delayed rewards in alcohol abusers compared to controls, and especially steep discounting among current users. Rapid discounting of delayed rewards may be a feature related to addictive disorders. A better understanding of how delaying rewards in time impacts their value may have implications for treatment.

Comparison of problem-gambling and non-problem-gambling youths seeking treatment for marijuana abuse.

OBJECTIVE: To evaluate the prevalence and correlates of problem gambling (PG) in marijuana-abusing adolescents. METHOD: A retrospective analysis was conducted of data collected from participants entering treatment for marijuana abuse in Philadelphia, Pennsylvania, and Hartford, Connecticut, between 1998 and 2000. RESULTS: Of 255 adolescents interviewed, 22% experienced gambling problems. Compared with non-problem gamblers (NPGs), PGs were more likely to be male, of African-American ethnicity, and to live in single-parent homes. Multivariate general linear models compared the two groups with respect to psychosocial problems. After controlling for age, gender, and race, differences between the groups emerged in drug use severity, legal difficulties, psychiatric problems, and human immunodeficiency virus risk behaviors. PGs reported a greater frequency of overall drug and alcohol use and greater intensity of marijuana use than their NPG counterparts. They had more illegal activity and greater somatization and anxiety symptoms, as well as higher levels of victimization. Compared with NPGs, PGs also reported more recent sexual partners. CONCLUSIONS: These data suggest that PG is common in marijuana-abusing youths and that they have increased psychosocial problems. These data suggest the need for early identification and treatment of PG in substance-abusing adolescents.

Gambling problems in substance abusers are associated with increased sexual risk behaviors.

OBJECTIVES: This study evaluated the association between gambling problems and HIV risk behaviors in substance abusers. PARTICIPANTS AND SETTING: One hundred and thirty-four substance abusers were recruited from advertisements placed in newspapers and at social service agencies. INTERVENTION: Gambling problems were assessed using the South Oaks Gambling Screen (SOGS). The Addiction Severity Index evaluated drug and psychosocial problems, and the HIV Risk Behavior Scale assessed risk behaviors. FINDINGS: Based on SOGS scores, 24% (n = 31) of substance abusers evidenced probable pathological gambling. Problem gambling substance abusers were more likely to be male than non-problem gamblers, but no other differences in demographic characteristics or drug use variables were noted. Compared to non-problem gamblers, problem gamblers reported more sex partners and less frequent use of condoms with casual and paid sex partners. Stepwise logistic regression confirmed the association between severity of gambling problems and more risky sexual behaviors; higher SOGS scores predicted having more than 50 sex partners, exchanging sex for drugs/money, and engaging in anal intercourse (p < 0.05). Participants with gambling problems were also less knowledgeable about HIV transmission. CONCLUSIONS: These data suggest that gambling problems may be a risk factor for contracting HIV. Increased efforts are needed to screen for and treat gambling problems among substance abusers.

Effects of increasing income on polydrug use: a comparison of heroin, cocaine and alcohol abusers.

AIMS: To assess how income affects hypothetical drug and non-drug purchasing decisions. PARTICIPANTS AND SETTING: Ninety-four subjects (26 heroin abusers, 28 cocaine abusers, 15 alcohol abusers and 25 non-drug using controls) were recruited from advertisements. INTERVENTION: Subjects were exposed to six conditions in which they "purchased" drugs as well as food, housing, and entertainment as income rose from $30 to $560 per day. FINDINGS: Heroin abusers selected significantly more hypothetical heroin and cocaine as income rose and demand for these two drugs was income elastic, with purchases rising in greater proportion than income. Cocaine abusers significantly increased purchases of, and showed income elastic demand for, cocaine and alcohol. Among alcohol abusers, significant increases in purchases and income elastic demand were found for alcohol and cigarettes, but not for other drugs. Across all four groups, demand for rent and food were income inelastic, such that purchases did not rise in proportion to the changes in income, while demand for entertainment was income elastic. Hypothetical choices were reliable between and within subjects, and drug choices were correlated with urinalysis results and life-time years of drug use. CONCLUSIONS: Income is an important variable in understanding choices for drug and non-drug commodities across a variety of substance-abusing populations.

Polydrug abuse in heroin addicts: a behavioral economic analysis.

AIM: To assess how price and income affect hypothetical drug-purchasing decisions of polydrug abusers undergoing treatment for heroin addiction. PARTICIPANTS, DESIGN AND SETTING: Forty subjects participated in experiments in which they hypothetically "purchased" drugs as price or income varied. INTERVENTION: Experiment 1 examined effects of heroin price on purchases of heroin, valium, cocaine, marijuana and alcohol. Experiment 2 examined the effects of both heroin and valium prices on purchases of these drugs. In both these experiments, income remained constant. Experiment 3 examined the effects of increasing income on drug choices, with drug prices constant. FINDINGS: As price of heroin rose in Experiment 1, heroin purchases decreased. Reductions in heroin purchases were proportionally less than price increases, demonstrating inelastic demand for heroin. Valium and cocaine purchases increased as heroin price rose, and cross-price elasticity coefficients indicated that these drugs substituted for heroin. In Experiment 2, demand for both heroin and valium was inelastic. Valium substituted for heroin, but heroin purchases were independent of valium prices, suggesting an asymmetrical substitution effect. Marijuana and alcohol purchases were independent of valium price, but both these drugs substituted for heroin. In Experiment 3 demand for heroin and cocaine was income elastic, with purchases rising in greater proportion than income. Marijuana, alcohol and valium purchases did not vary with income, demonstrating that demand for these drugs was income inelastic. Hypothetical choices were reliable both between and within subjects. Moreover, drug choices in this hypothetical situation were correlated with urinalysis results, demonstrating initial validity of this methodology. CONCLUSIONS: This methodology may be useful for understanding the phenomenon of polydrug abuse.

Shortened time horizons and insensitivity to future consequences in heroin addicts.

AIMS: To investigate whether heroin addicts demonstrate shortened time horizons and decreased sensitivity to future consequences of their behavior compared to non-drug users. DESIGN SETTING AND PARTICIPANTS: Thirty-four heroin addicts enrolled in a buprenorphine treatment clinic and 59 non-drug-using controls completed a personality questionnaire and two laboratory tasks. MEASUREMENTS: The Stanford Time Perception Inventory (STPI) personality questionnaire assessed orientation to the future, and the Future Time Perspective (FTP) task elicited predictions of the timing and ordering of future events. The Bechara card task measured preferences for decks of cards that range in magnitude and probability of delayed and immediate rewards and punishers. FINDINGS: Heroin addicts scored significantly lower than controls on the STPI scale indicative of future orientation. In the FTP, heroin addicts were less likely to predict events far into the future and less likely to systematically organize events in the future. In the card task, heroin addicts were less likely to win money than controls. They were more likely to play from a deck that contained greater immediate gains but that resulted in large, delayed punishers and overall net losses. They also made fewer selections from a deck that provided an overall net gain via relatively low immediate rewards and frequent small punishments. CONCLUSIONS: Shortened time horizons and decreased sensitivity to delayed consequences may explain drug abusers' persistent use of drugs, despite the long-term negative consequences associated with drug use.

Examining the limits of the buprenorphine interdosing interval: daily, every-third-day and every-fifth-day dosing regimens.

AIMS: Opioid-dependent outpatients may be more likely to present for pharmacological treatment if less than daily dosing can be arranged. These studies compared opioid withdrawal symptoms during 24-, 72-, and 120-hour buprenorphine dosing regimens and evaluated participants' preferences for these different dosing regimens. PARTICIPANTS: Thirty-three opioid-dependent participants received daily sublingual maintenance doses of 4 mg/70 kg (n = 14) or 8 mg/70 kg (n = 19) of liquid buprenorphine. METHODS: In Study I participants received, in a random order, three dosing regimens for five repetitions of each: daily maintenance doses every 24 hours (4 or 8 mg/70 kg), triple the daily maintenance dose every 72 hours (12 or 24 mg/70 kg) and quintuple the daily maintenance dose every 120 hours (20 or 40 mg/70 kg). Doses were administered under double-blind procedures, and placebos were administered on the interposed days during the latter two regimens. Subjective and observer ratings of opioid withdrawal symptoms were assessed daily prior to receipt of each dose. In Study II, a new group of participants received each of the three dosing regimens under open-dosing procedures and then chose between the different dosing regimens. FINDINGS: Opioid withdrawal symptoms increased significantly during the every-fifth-day dosing regimen in both the blind- and open-dosing studies. In the choice phase of Study II, only one participant (7%) chose quintuple-every-fifth-day dosing over all other dosing options. CONCLUSIONS: These results suggest that the maximum duration of action of buprenorphine is less than 5 days when five times the daily maintenance dose is provided.

A comparison of four buprenorphine dosing regimens using open-dosing procedures: is twice-weekly dosing possible?

AIMS: To compare opioid withdrawal symptoms during 24-, 48-, 72- and 96-hour buprenorphine dosing regimens and to evaluate subjects' preferences for these different dosing schedules. SUBJECTS: Fourteen opioid-dependent subjects participated in this study. They received daily sublingual maintenance doses of 4 mg/70 kg (n = 4) or 8 mg/70 kg (n = 10) of buprenorphine. INTERVENTION: In the first study subjects received, in a random order, four dosing regimens for five repetitions of each: daily maintenance doses every 24 hours (4 or 8 mg/70 kg), double the daily maintenance dose every 48 hours (8 or 16 mg/70 kg), triple the daily maintenance dose every 72 hours (12 or 24 mg/70 kg), and quadruple the daily maintenance dose every 96 hours (16 or 32 mg/70 kg). Measures of subjective and observer opioid withdrawal symptoms were assessed prior to receipt of each dose. In a second study, subjects chose between the different dosing regimens. FINDINGS: Some withdrawal ratings increased during the less frequent dosing schedules in the first study. In the second study, 46% of subjects preferred the quadruple-every-fourth-day dosing regimen over every other option, and only 14% preferred to be dosed daily. CONCLUSIONS: These results suggest that some opioid-dependent outpatients are willing and able to endure the withdrawal symptoms associated with less than daily dosing, and a twice-weekly dosing regimen may be possible.

Give them prizes, and they will come: contingency management for treatment of alcohol dependence.

This study evaluated the efficacy of a contingency management (CM) procedure that provided opportunities to win prizes as reinforcers. At intake to outpatient treatment, 42 alcohol-dependent veterans were randomly assigned to receive standard treatment or standard treatment plus CM, in which they earned the chance to win prizes for submitting negative Breathalyzer samples and completing steps toward treatment goals. Eighty-four percent of the CM participants were retained in treatment for an 8-week period compared with 22% of the standard treatment participants (p < .001). By the end of the treatment period, 69% of those receiving CM were still abstinent, but 61% of those receiving standard treatment had used alcohol (p < .05). These results support the efficacy of this CM procedure. Participants earned an average of $200 in prizes. This CM procedure may be suitable for use in standard treatment settings because prizes can be solicited from the community.

Pathological gamblers, with and without substance use disorders, discount delayed rewards at high rates.

Pathological gambling is classified as a disorder of impulse control, yet little research has evaluated behavioral indices of impulsivity in gamblers. The rates at which rewards delayed in time are subjectively devalued may be a behavioral marker of impulsivity. This study evaluated delay discounting in 60 pathological gamblers and 26 control participants. Gamblers were divided into those with (n = 21) and without (n = 39) substance use disorders. A hypothetical $1,000 reward was delayed at intervals ranging from 6 hr to 25 years, and immediate rewards varied from $1 to $999. Pathological gamblers discounted delayed rewards at higher rates than control participants, and gamblers with substance use disorders discounted delayed rewards at higher rates than non-substance-abusing gamblers. These data provide further evidence that rapid discounting of delayed rewards may be a feature central to impulse control and addictive disorders, including pathological gambling.

Substance abuse, pathological gambling, and impulsiveness.

This study evaluated behavioral and self-report indices of impulsiveness in pathological gambling substance abusers (n=27), non-pathological gambling substance abusers (n=63), and non-pathological gambling/non-substance abusing controls (n=21). The Bechara card task measured preferences for decks of cards that ranged in magnitude and probability of delayed and immediate rewards and punishers. The Stanford Time Perception Inventory (STPI) assessed orientation to the future, the Zuckerman Sensation Seeking Scale evaluated sensation seeking, and the Eysenck and Barratt scales measured impulsivity. A Principal Components analysis revealed that these personality measures comprised three distinct measures of impulsivity: impulse control, novelty seeking and time orientation. Linear contrast analyses revealed that substance abuse and pathological gambling resulted in additive effects on the impulse control and time orientation factors, but not on the novelty-seeking scale. Performance on the card task did not correlate with any of the three factors derived from the personality scale scores, but the presence of both substance abuse and pathological gambling had an additive effect on preferences for decks containing greater immediate gains but resulting in large punishers and overall net losses. These results provide further evidence of an association among substance abuse, pathological gambling, and impulsivity.

A behavioral economic analysis of polydrug abuse in alcoholics: asymmetrical substitution of alcohol and cocaine.

Economic concepts can be used to assess how drug prices affect consumption patterns. Increases in price for a commodity typically result in reductions in consumption. Demand is considered elastic if decreases in consumption are proportionally greater than increases in price, and inelastic if they are proportionally smaller than rises in price. The price of one commodity can also affect consumption of others. Commodities can function as substitutes, complements or independents, and these concepts refer to increases, decreases, or no change in the consumption of one item as the price of another increases. This study evaluated the effects of drug prices on hypothetical drug-purchasing decisions in 53 alcohol abusers. Experiments 1, 2, and 3 examined how alcohol, cocaine, and Valium prices, respectively, influenced purchases of alcohol, cocaine, Valium, heroin, marijuana and nicotine. As price of alcohol rose in Experiment 1, alcohol purchases decreased and demand for alcohol was inelastic. Cocaine was a complement to alcohol, but other drugs purchases were independent of alcohol prices. In Experiment 2, demand for cocaine was elastic as its price increased. Alcohol was a substitute for cocaine, but other drug purchases did not change significantly. In Experiment 3, demand for Valium was elastic as its price rose, and all other drug purchases were independent of Valium prices. Hypothetical choices were reliable between and within subjects and associated with urinalysis results and lifetime histories of drug abuse. These results suggest that, among alcohol abusers, cocaine is a complement to alcohol, but alcohol is a substitute for cocaine.

A comprehensive guide to the application of contingency management procedures in clinical settings.

Controlled clinical research has demonstrated the efficacy of contingency management procedures in treating substance use disorders. Now is the time to begin introducing these procedures into standard clinical practice. This article reviews the rationale of contingency management interventions and provides a review of representative scientific work in the area. It also discusses behaviors that can be modified, reinforcers that can be used, and behavioral principles that can be adapted to improve outcomes. This paper provides practical advice and a guideline for clinicians and researchers to use when designing and administering contingency management interventions. The recommendations are based on empirically validated manipulations. Areas in which more research is needed are suggested as well.