Louis A. Giordano

Mild opioid deprivation increases the degree that opioid-dependent outpatients discount delayed heroin and money

HeadingAbstractRationale. A growing literature suggests that excessive temporal discounting of delayed rewards may be a contributing factor in the etiology of substance abuse problems. Little is known, however, about how drug deprivation may affect temporal discounting of delayed rewards by drug-dependent individuals.Objective. To examine the extent to which opioid deprivation affects how opioid-dependent individuals discount small, medium and large quantities of delayed heroin and money.Methods. Thirteen opioid-dependent individuals maintained on buprenorphine completed a hypothetical choice task in which they choose between a constant delayed reward amount and an immediate reward amount that was adjusted until they expressed indifference between both outcomes. The task was completed for three values of heroin and money rewards during eight sessions under conditions of opioid deprivation (four sessions) and satiation (four sessions).Results. Across conditions, hyperbolic functions provided a good fit for the discounting data. Degree of discounting was significantly higher when subjects were opioid deprived. Consistent with previous findings, degree of discounting was higher for heroin than money and inversely related to the magnitude of the reward.Conclusion. Opioid deprivation increased the degree to which dependent individuals discounted delayed heroin and money. Understanding the conditions that affect how drug-dependent individuals discount delayed rewards might help us understand the myopic choices made by such individuals and help improve treatment outcomes.

The effects of reduced cigarette smoking on discounting future rewards: An initial evaluation

To determine whether reduction of smoking via contingency management in depen-dent smokers would decrease the discounting of delayed reinforcers compared with smokers who did not reduce their smoking, moderate to heavy cigarette smokers were randomly assigned to one of two conditions: a contingency management condi-tion and a control condition. In three phases (baseline discounting determination for hypothetical money and cigarettes, implementation of a contingency management or control condition, and postintervention discounting determination), the procedure to reinforce reduction in cigarette smoking produced CO decreases in all subjects exposed to that procedure. Discounting decreased significantly for both cigarettes and money among the group for whom smoking reductions were reinforced, whereas the control group showed no significant change for either commodity. Reductions in smoking can lead to reductions in discounting, and increased discounting in current smokers may be a reversible effect of nicotine dependence.

Neuroactive steroids, negative affect, and nicotine dependence severity in male smokers

RationaleNicotine administration alters neuroactive steroids in rodent models, and serum levels of the neuroactive steroid DHEAS (dehydroepiandrosterone sulfate) appear to be higher in smokers. These molecules may be relevant to tobacco addiction and affective symptoms.ObjectivesThis study aims to investigate DHEAS, allopregnanolone, pregnenolone, and other steroids in male smokers to determine potential associations with nicotine dependence severity and negative affect.Materials and methodsAllopregnanolone and pregnenolone serum levels were determined by gas chromatography/mass spectrometry, while DHEAS and other steroid levels were determined by radioimmunoassay in 28 male smokers. Correlational analyses were performed to determine potential associations with rating measures, including the Fagerstrom Test for Nicotine Dependence (FTND), the addiction subscale of the Ikard Smoking Motivation Questionnaire (ISMQ), the craving item on the Reasons to Smoke (RTS) Questionnaire, and the negative affect and craving subscales of the Shiffman–Jarvik Withdrawal Questionnaire.ResultsDHEAS levels were inversely correlated with the negative affect subscale of the Shiffman–Jarvik Withdrawal Questionnaire (r=−0.60, p=0.002) and the RTS craving item (r=−0.43, p=0.03), and tended to be inversely correlated with the FTND scores (r=−0.38, p=0.067) and the ISMQ addiction subscale (r=−0.38, p=0.059), adjusting for age. Allopregnanolone levels were positively correlated with cotinine levels (r=0.57, p=0.006); pregnenolone levels tended to be positively correlated with cotinine levels (r=0.40, p=0.066).ConclusionsDHEAS levels were inversely correlated with negative affect and craving measures, and may predict nicotine dependence severity. Allopregnanolone levels were positively correlated with cotinine levels, suggesting that this neuroactive steroid may be upregulated in smokers. Neuroactive steroids may represent novel smoking cessation agents.

Sensitivity of nicotine-containing and de-nicotinized cigarette consumption to alternative non-drug reinforcement: a behavioral economic analysis.

A previous report from our laboratory showed similar measures of reinforcing efficacy for nicotine‐containing and de‐nicotinized cigarettes when each cigarette type was presented alone. The present experiment further compared the reinforcing efficacy of nicotine‐containing and de‐nicotinized cigarettes by assessing the effects of alternative non‐drug reinforcement on self‐administration of both cigarette types. Eight human subjects responded on a progressive‐ratio schedule in which the number of plunger pulls required for standardized cigarette puffs increased across sessions. Responding for the two types of cigarette was examined when each was available alone and when the concurrent opportunity to earn money was available. Consumption of nicotine‐containing and de‐nicotinized cigarettes was decreased by both increases in price and by the concurrent availability of money. The two cigarettes types did not differ in their sensitivity to price or alternative non‐drug reinforcement. These results replicate our previous report of similar measures of reinforcing efficacy for the two cigarette types when each was presented alone, and extend our previous findings to a choice situation involving an alternative non‐drug reinforcer. These data suggest the importance of further examination of non‐pharmacological variables in the maintenance of drug taking and the sensitivity of drug taking to alternative non‐drug sources of reinforcement. Factors potentially contributing to the maintenance of smoking the de‐nicotinized cigarettes (i.e. conditioned reinforcement, primary reinforcement by respiratory stimulation, instructional control, demand characteristics) are also discussed.

Implementation of a Smoking Cessation Treatment Study at Substance Abuse Rehabilitation Programs: Smoking Behavior and Treatment Feasibility Across Varied Community-based Outpatient Programs.

Cigarette smoking is widely prevalent among individuals in treatment for drug or alcohol dependence; however, the treatment of nicotine addiction in this population has numerous obstacles at both programmatic and patient levels. Despite these difficulties, recent studies have demonstrated moderate success in implementing smoking cessation treatment in drug rehabilitation programs. The National Drug Abuse Treatment Clinical Trials Network sponsored a smoking cessation study in 13 community-based outpatient substance abuse rehabilitation programs across the country. The study evaluated the effectiveness of smoking cessation treatment provided as an adjunct to substance abuse treatment-as-usual. This report summarizes the practical and clinical experiences encountered at each of the study sites with regard to implementing the smoking cessation treatment intervention. Smoking behavior of the treatment clientele was assessed by anonymous survey at each site. In addition, sites were systematically characterized by using program review and assessment tools completed by the respective staff and program directors at the site. Survey and recruitment data indicated that cigarette smoking is more prevalent and that smoking cessation treatment is more feasible, in methadone maintenance treatment programs. Other factors associated with smoking behavior and with the recruitment of drug- and alcohol-dependent individuals into the smoking cessation treatment study are described.

Behavioral Economics of Human Drug Self-Administration: Progressive Ratio vs. Random Sequences of Response Requirements

Progressive‐ratio (PR) schedules have been used widely to examine the relationship between drug consumption and drug price (i.e. demand curves) in the study of the behavioral economics of drug abuse. Sequential effects produced by the increasing response requirements of progressive‐ratio schedules might influence the shape of demand curves for drug reinforcers. This study compared progressive ratio schedule and random sequences of ratio requirements, each incremented across sessions in a within‐subject design, to determine if they produced similar behavioral economic and traditional measures of reinforcer efficacy. Self‐administration of standardized cigarette puffs (70 cc each) was studied with eight smokers. Puffs were available at nine ratio requirements (e.g. 3, 100, 300, 600, 1500, 3000, 6000, 12 000, 24 000 responses/three puffs), presented in ascending (progressive‐ratio schedule) or random sequence across daily sessions. The parameter estimates obtained on measures of reinforcing efficacy (e.g. breakpoint, peak response rates, elasticity of demand) were similar for both methods of incrementing prices. We found no evidence that PR and random sequences of fixed‐ratio (FR) schedules, incremented across daily sessions, resulted in different demand curves.