Biomedical subjects

Suchitra Krishnan-Sarin

Publications and source records attributed to Suchitra Krishnan-Sarin.

At least 19 recordsLinked to original sources

PubMed2006

Behavioral impulsivity predicts treatment outcome in a smoking cessation program for adolescent smokers.

OBJECTIVE: To examine the relationship between impulsivity and smoking cessation treatment response among adolescents. METHODS: Thirty adolescent smokers participated in a high school based smoking cessation program combining contingency management and cognitive behavioral therapy. Self-report (Barratt impulsiveness scale (BIS-II); Kirby delay discounting measure (DDM)) and behavioral (experiential discounting task (EDT); continuous performance task (CPT)) measures of impulsivity were assessed at treatment onset. RESULTS: Sixteen participants (53%) were abstinent from smoking at completion of the four-week study. Compared to abstinent adolescents, those not achieving abstinence discounted monetary rewards more on the EDT and committed more commission errors on the CPT. Group differences were not observed on the BIS-II or DDM. CONCLUSIONS: These preliminary results suggest that specific behavioral measures of impulsivity may be associated with the ability to initiate and/or maintain abstinence from smoking among adolescent smokers.

Adolescent↗

PubMed2006

Modeling the effect of alcohol on smoking lapse behavior.

OBJECTIVE: The primary aim of this project was to examine the role of alcohol use in smoking lapse behavior, as alcohol consumption is a known risk factor for poor smoking cessation outcomes. MATERIALS AND METHODS: We have developed a novel human laboratory model to examine two primary aspects of alcohol-mediated tobacco relapse: (1) Does alcohol facilitate the initiation of the first cigarette? (2) Once the first cigarette is initiated, does alcohol facilitate subsequent smoking? Using a within-subject design, 16 daily smokers who were also heavy social drinkers received a priming drink (0.03 g/dl or taste-masked placebo) and then had the option of initiating a tobacco self-administration session or delaying initiation by 5-min increments for up to 50 min in exchange for monetary reinforcement. Subsequently, the tobacco self-administration session consisted of a 1-h period in which subjects could choose to smoke their preferred brand of cigarettes using a smoking topography system or receive monetary reinforcement for cigarettes not smoked. Alcohol craving, tobacco craving, subjective reactivity to alcohol, and nicotine withdrawal were assessed as secondary outcomes. RESULTS: Results demonstrated that after consuming the alcohol beverage, subjects were less able to resist the first cigarette and initiated their smoking sessions sooner, and smoked more cigarettes compared to the placebo beverage. These findings have implications for smoking cessation in alcohol drinkers and model development to assess smoking lapse behavior.

Adult↗

PubMed2006

Human tobacco smokers in early abstinence have higher levels of beta2* nicotinic acetylcholine receptors than nonsmokers.

Nicotine, the addictive chemical in tobacco smoke, initiates its actions in brain through nicotinic acetylcholine receptors (nAChRs). In particular, nAChRs containing beta2-subunits (beta2*-nAChRs) the most prevalent subtype, mediate the reinforcing properties of nicotine. We hypothesized that abnormal numbers of beta2*-nAChRs during early abstinence contribute to the perpetuation of addiction to tobacco smoking. Using molecular imaging, specifically single-photon emission computed tomography with the nAChR agonist radiotracer [123I]5-IA-85380 ([123I]5-IA), we imaged beta2*-nAChR availability in human smokers. First, using nonhuman primates treated chronically with nicotine, we estimated the time interval necessary for smokers to abstain from smoking so that residual nicotine would not interfere with [123I]5-IA binding to the beta2*-nAChR as approximately 7 d. Thus, we imaged human smokers at 6.8 +/- 1.9 d (mean +/- SD) of abstinence. Abstinence was confirmed by daily assessments of urinary cotinine and expired carbon monoxide levels. In smokers, [123I]5-IA uptake was significantly higher throughout the cerebral cortex (26-36%) and in the striatum (27%) than in nonsmokers, suggesting higher beta2*-nAChR in recently abstinent smokers. Beta2*-nAChR availability in recently abstinent smokers correlated with the days since last cigarette and the urge to smoke to relieve withdrawal symptoms but not the severity of nicotine dependence, severity of nicotine withdrawal, or the desire to smoke. Higher brain beta2*-nAChR during early abstinence indicates that, when smokers quit smoking, they do so in the face of a significant increase in the receptors normally activated by nicotine. Greater beta2*-nAChR availability during early abstinence may impact the ability of smokers to maintain abstinence.

Adult↗

PubMed2006

Characteristics of adolescent past-year gamblers and non-gamblers in relation to alcohol drinking.

A preliminary examination of mental health and gambling characteristics as a function of alcohol use in adolescents was conducted in a nationally representative sample of 16- and 17-year-olds using data from the 1998 Gambling Impact and Behavior Study. Adolescents were stratified by past-year alcohol use into abstainers/low-frequency (ALF) drinkers and moderate to high-frequency (MHF) drinkers as done previously [Desai, R. A., Maciejewski, P. K., Pantalon, M. V., & Potenza, M. N. (in press). Gender differences among recreational gamblers: Association with the frequency of alcohol use. Psychology of Addictive Behaviors]. A greater proportion of MHF drinkers reported past-year gambling than did ALF drinkers (66.1% vs. 38.2%). In the ALF drinking group but not the MHF one, past-year gambling was associated with dysphoria/depression (odds ratio for ALF: 1.94, odds ratio for MHF: 0.88) and drug use (odds ratio for ALF: 2.57, odds ratio for MHF: 0.49). A significant gambling-by-alcohol-use group interaction was observed for drug use (p<0.01). Among past-year gamblers, MHF drinkers were more likely than ALF ones to report frequent gambling. These results suggest a complex relationship between gambling alcohol use, drug use, and mental health in adolescents.

Adolescent↗

PubMed2006

A decrease in the plasma DHEA to cortisol ratio during smoking abstinence may predict relapse: a preliminary study.

RATIONALE: Increases in depressive symptoms during smoking cessation have been associated with risk for relapse. Several studies have linked plasma levels of cortisol and dehydroepiandrosterone (DHEA) or DHEA-sulfate (DHEAS) to depressive symptoms. OBJECTIVES: To determine whether changes in plasma cortisol, DHEA, or DHEAS levels and emergence of depressive symptoms during smoking cessation are associated with smoking relapse. MATERIALS AND METHODS: Subjects were healthy non-medicated men and women, aged 39+/-12 years, who smoked, on average, 22 cigarettes per day. Depressive symptoms, smoking withdrawal symptoms, and plasma steroid levels were measured before and after 8 days of verified smoking abstinence. Relapse status at day 15 was then determined. RESULTS: In the full sample (n=63), there was a trend for changes in depressive symptoms to be associated with relapse. In the subset of 25 subjects with plasma neuroactive steroid data, there was a significant interaction between the change in the plasma DHEA/cortisol ratio from day 0 to day 8 and relapse status at day 15. This ratio was similar before abstinence, but lower at day 8 in relapsed, compared to abstinent, subjects. Changes in the DHEA/cortisol ratio tended to predict changes in depressive symptoms in the women only. CONCLUSION: A decrease in the plasma DHEA/cortisol ratio during 8 days of smoking abstinence was associated with relapse over the following week. Further research is needed to fully characterize sex-specific relationships between abstinence-induced changes in neuroactive steroid levels, depressive or withdrawal symptoms, and relapse. Such research may lead to new interventions for refractory smoking dependence.

Adult↗

PubMed2006

Gender and weight concerns in adolescent smokers.

The aim of this study was to examine smoking-specific weight concerns in a well-characterized sample of adolescent daily smokers and the influence of gender, age, and body mass index (BMI). Adolescent smokers (n=103) were asked two smoking-specific weight concern questions: "How much do cigarettes help you control your weight?" and "How concerned are you about gaining weight as a result of quitting?" A significant positive relationship was found between average daily cigarette use and belief in smoking as a means to control weight and a significant negative relationship between the years of smoking and belief that smoking controls weight. There was no significant relationship between BMI and smoking to control weight for females, whereas for males, there was a positive relationship, indicating that heavier males were more likely to report smoking to control weight. Additionally, females who smoked more cigarettes reported more concern about gaining weight upon quitting, a pattern not seen in males. Results highlight potentially important gender differences in the relationship between weight concerns and smoking and the influence these concerns may have on quitting smoking.

Adolescent↗

PubMed2006

A controlled trial of naltrexone augmentation of nicotine replacement therapy for smoking cessation.

BACKGROUND: Many smokers remain refractory to current therapies, which only partially address weight gain after smoking cessation. Thus, this study evaluated whether naltrexone hydrochloride augmentation of nicotine patch therapy improves smoking abstinence and reduces postcessation weight gain more than nicotine patch therapy alone and at what dose. METHODS: Six-week double-blind placebo-controlled trial with follow-up in an outpatient research center. Four hundred individuals who smoked 20 or more cigarettes daily were randomly assigned to treatment for 6 weeks with a 21-mg nicotine patch and oral naltrexone hydrochloride (0, 25, 50, or 100 mg/d) after equal random treatment assignment and followed up for 1 year after randomization. The a priori specified primary end points were prolonged 4-week cigarette abstinence after a 2-week grace period in the intent-to-treat sample and weight gain in these abstainers. RESULTS: We found no significant differences in prolonged 4-week abstinence (P = .49) or 6-week continuous abstinence after the quit date (P = .12) during treatment in the intent-to-treat analysis. Among 295 treatment completers, the 100-mg dose was associated with higher continuous abstinence rates (71.6%) compared with placebo (48%) (odds ratio, 2.73; 95% confidence interval, 1.39-5.39; P<.01). Among continuous abstainers, the 25-mg naltrexone hydrochloride group gained significantly less weight (mean +/- SEM, 0.7 +/- 0.31 kg) than the placebo group (mean +/- SEM, 1.9 +/- 0.33 kg; P<.01). Similar naltrexone dose effects on weight were found for those with prolonged abstinence and treatment completers, irrespective of abstinence. CONCLUSIONS: The 100-mg dose of naltrexone hydrochloride appears the most promising for augmenting the efficacy of the nicotine patch on smoking cessation outcomes but requires further study. The significant weight reduction with low-dose naltrexone therapy suggests that it may be useful as a second-line treatment for weight-concerned smokers.

Administration, Cutaneous↗

PubMed2006

Smoking as a complex but critical covariate in neurobiological studies of posttraumatic stress disorders: a review.

As smoking rates in the general population continue to fall in response to new information and changing social values, the continued high rate of smoking among persons with psychiatric disorders has caught the attention of society at many levels: public health officials, medical and mental health care providers, and concerned family members alike. As a consequence, research studies aimed at quantifying the problem and understanding its cause have increased dramatically over the past several years. The following review first examines epidemiological studies that have revealed a bidirectional causal relationship between tobacco dependence and posttraumatic stress disorder (PTSD), one of several mental health disorders in which tobacco dependence remains prevalent and resistant to intervention. Second, we use a translational neuroscience perspective to discuss possible neurobiological mediators of the relationship between PTSD and tobacco dependence, hoping to spur further human and animal research that will elucidate pathogenetic mechanisms involved and inspire novel treatment interventions. Finally, to enable more effective clinical research in this area, we provide an overview of effective scientific methods for assessing and managing 'smoking status' as an experimental variable in clinical research studies of PTSD as well as other mental health disorders.

Animals↗

PubMed2006

Contingency management for smoking cessation in adolescent smokers.

This pilot study evaluated the use of contingency management (CM) procedures in combination with cognitive-behavioral therapy (CBT) for smoking cessation in adolescents. Twenty-eight treatment-seeking adolescent smokers participated in a 1-month, school-based smoking cessation program and were randomly assigned to receive either CM with weekly CBT or CBT alone. In the CM+CBT group, biochemical verification of abstinence was obtained twice daily during the first 2 weeks, followed by daily appointments during the 3rd week and once every other day during the 4th week. Participants were monetarily reinforced for abstinence on an escalating magnitude schedule with a reset contingency. At the end of 1 week and 1 month of treatment, abstinence verified using quantitative urine cotinine levels was higher in participants in the CM+CBT group (1 week: 76.7%; 1 month: 53.0%) when compared with the CBT-alone group (1 week: 7.2%; 4 weeks: 0%). These preliminary results provide a strong initial signal supporting the utility of CM techniques for smoking cessation in adolescents and demonstrate the feasibility of implementing such a program in a school setting.

Adolescent↗

PubMed2005

Effects of cigarette smoking on spatial working memory and attentional deficits in schizophrenia: involvement of nicotinic receptor mechanisms.

BACKGROUND: Cigarette smoking rates in schizophrenia are higher than in the general population. OBJECTIVES: To determine whether cigarette smoking modifies cognitive deficits in schizophrenia and to establish the role of nicotinic acetylcholine receptors (nAChRs) in mediating cigarette smoking-related cognitive enhancement. DESIGN: Neuropsychological assessments were performed at smoking baseline, after overnight abstinence, and after smoking reinstatement across 3 separate test weeks during which subjects were pretreated in a counterbalanced manner with the nonselective nAChR antagonist mecamylamine hydrochloride (0, 5, or 10 mg/d). PARTICIPANTS: Twenty-five smokers with schizophrenia and 25 control smokers. SETTING: Outpatient mental health center. MAIN OUTCOME MEASURES: Visuospatial working memory (VSWM) and Continuous Performance Test (CPT) scores. RESULTS: In smokers with schizophrenia and control smokers, overnight abstinence led to undetectable plasma nicotine levels and an increase in tobacco craving. While abstinence reduced CPT hit rate in both groups, VSWM was only impaired in smokers with schizophrenia. Smoking reinstatement reversed abstinence-induced cognitive impairment. Enhancement of VSWM and CPT performance by smoking reinstatement in smokers with schizophrenia, but not the subjective effects of smoking, was blocked by mecamylamine treatment. CONCLUSIONS: Cigarette smoking may selectively enhance VSWM and attentional deficits in smokers with schizophrenia, which may depend on nAChR stimulation. These findings may have implications for understanding the high rates of smoking in schizophrenia and for developing pharmacotherapies for cognitive deficits and nicotine dependence in schizophrenia.

Adult↗

PubMed2005

Daily patterns of alcohol, cigarette, and marijuana use in adolescent smokers and nonsmokers.

Timeline followback (TLFB) methodology was used to assess the daily use of cigarettes, alcohol, and marijuana in adolescent cigarette smokers and nonsmokers over the prior 30 days. Adolescent smokers reported more frequent daily use of both alcohol and marijuana than nonsmokers did. Of those smokers and nonsmokers who drank alcohol and used marijuana, smokers reported more frequent daily use of alcohol, but not marijuana. In examining daily use patterns, there were very few instances when adolescent smokers used alcohol but did not smoke cigarettes, and smokers used marijuana alone on more days than alcohol alone. One-fifth of the adolescent smokers used all three substances on the same day in the past month. There were no significant differences in the patterns of alcohol and marijuana use between female and male smokers, regardless of age. Implications for clinical interventions and future research are discussed.

Adolescent↗

PubMed2005

Perceived risks and benefits of smoking cessation: gender-specific predictors of motivation and treatment outcome.

The primary aim of this study was to examine gender differences in perceived risks and benefits of smoking cessation and their relationship to pretreatment motivation and treatment outcome. No validated measures that comprehensively assess perceived risks and benefits associated with smoking cessation were available in the literature; consequently, we developed a self-report instrument [Perceived Risks and Benefits Questionnaire (PRBQ)] for this purpose. A sample of 573 treatment-seeking smokers (48% female) entering smoking cessation trials completed the PRBQ, and its association with treatment outcome was assessed in a subsample of 93 participants. Overall, the PRBQ demonstrated good psychometric properties. Females indicated greater likelihood ratings of perceived risks and benefits than males. For women and men, perceived benefits were positively associated with motivation, and perceived risks were negatively associated with motivation and treatment outcome. Women evidenced stronger associations between perceived risks and pretreatment motivation, and treatment outcome. Knowledge of perceived risks and benefits associated with smoking cessation is critical for public education campaigns and could inform intervention strategies designed to modify sex-specific beliefs associated with lowered behavioral intentions to quit smoking.

Attitude to Health↗

PubMed2005

Knowledge and perceived risk of smoking-related conditions: a survey of cigarette smokers.

BACKGROUND: Previous studies suggest that smokers minimize the personal health risk of smoking. Smokers may not be aware of the various smoking-related disease risks or believe that they are susceptible to them. METHODS: We presented 537 adult treatment-seeking smokers with a list of 34 medical conditions, of which 25 were smoking-related conditions, and 9 were nonsmoking-related items. Subjects were asked to identify which medical conditions were smoking-related, and to rate their perceived risk (using a 7-point Likert scale) of developing various smoking-related conditions if they continued to smoke. RESULTS: The average percentage of knowledge items correct for each disease category included cardiovascular (93%), pulmonary (94%), oral health diseases (89%), smoking-related cancers (71%), and reproductive risks (44%). Premature death was identified as a risk by 95% of smokers yet only 63.5% reported that disability could also result from smoking. Knowledge was associated with perceived risk of smoking-related illnesses across disease categories. CONCLUSIONS: Knowledge and perceived risk of cardiovascular, pulmonary, and oral disease was high among current smokers; knowledge and perceived risk of reproductive-related problems, and cancers other than lung cancer was much lower. Smokers recognize that smoking may result in premature death, but are less likely to acknowledge that smoking could result in a disability significantly affecting their quality of life.

Adolescent↗

PubMed2005

Suppression of the HPA axis stress-response: implications for relapse.

This article presents the proceedings of a symposium held at the meeting of the International Society for Biomedical Research on Alcoholism (ISBRA) in Mannheim, Germany, in October 2004. This symposium explored the potential role of hypothalamic-pituitary-adrenal (HPA) axis dysregulation upon relapse. HPA axis stimulation induces the release of the glucocorticoid cortisol, a compound with profound effects upon behavior and emotion. Altered stress-responses of the HPA axis in abstinent alcohol-dependent subjects, therefore, may influence their affective and behavioral regulation, thus impacting their potential for relapse. Bryon Adinoff began the symposium with a review of HPA axis dysfunction in alcohol-dependent subjects, including recent studies from his lab demonstrating an attenuated glucocorticoid response to both endogenous and exogenous stimulation in one-month abstinent men. Klaus Junghanns presented his work demonstrating that a blunted ACTH or cortisol response to subjective stressors (social stressor or alcohol exposure) is predictive of a return to early drinking. The final two presenters examined the interaction between naltrexone and HPA responsiveness in alcohol-dependent or at-risk subjects, as naltrexone induces an increase in ACTH and cortisol. Falk Kiefer discussed the relationship between basal HPA axis responsivity and clinical outcome following treatment with naltrexone or acamprosate. Plasma ACTH significantly decreased over the course of the study in the placebo group, but not the medication groups [corrected] Lower basal concentrations of ACTH and cortisol were associated with quicker relapse in the placebo group only. Suchitra Krishnan-Sarin described her preliminary work, in which family-history positive (FH+) and family history negative (FH-) subjects were administered naltrexone, followed by an assessment of alcohol-induced craving. The cortisol response to alcohol was significantly and inversely related to craving in the FH+, but not the FH-, subjects. Alterations in HPA axis responsivity may therefore have a negative impact upon clinical outcome in alcohol-dependent subjects, and disinhibition of the axis with medication may have therapeutic potential.

Adrenocorticotropic Hormone↗

PubMed2004

Revisiting the factor structure of the questionnaire on smoking urges.

This study assessed the factor structure of the Questionnaire on Smoking Urges (QSU), a commonly used assessment of cravings for cigarettes, with a sample of smokers presenting for treatment in a smoking cessation trial. On the basis of previous research, three confirmatory factor analytic models were tested. Model 1 hypothesized a 26-item, 2-factor model using the items reported in the original QSU analysis by S. T. Tiffany and D. J. Drobes (1991). Model 2 hypothesized a 12-item, 2-factor model comprised of the 6 most robust items found in each of the 2 factors of the original factor analysis. Using the 12 items from Model 2, Model 3 hypothesized a 12-item, 1-factor model. The 2nd model was found to fit the data best. Reliability was also tested using values obtained in this 2nd model, and these estimates were found to be reasonably good. Future research directions for the QSU are discussed.

Disruptive, Impulse Control, and Conduct Disorders↗

PubMed2004

Gender effects of reported in utero tobacco exposure on smoking initiation, progression and nicotine dependence in adult offspring.

We examined the relationship between self-reported in utero tobacco exposure and gender on smoking initiation, progression of cigarette use (i.e., telescoping), and current levels of nicotine dependence in adult treatment-seeking smokers. Subjects (N = 298) who reported "yes" (28% of the original sample) or "no" (50% of the original sample) to in utero tobacco exposure were included in the analyses. Telescoping was calculated as the difference between the age respondents smoked their "first full cigarette" and the age when they started smoking daily. Females who reported being exposed in utero transitioned from initial to daily cigarette use more rapidly than females not exposed. The opposite effect was found for males, which may be related to our finding that in utero exposure lowered the age of cigarette experimentation in exposed compared with unexposed males. Measures of current cigarette use and dependence (i.e., Fagerström Test for Nicotine Dependence, prior withdrawal, number of past year quit attempts) were significantly associated with reported in utero exposure, gender, or interactions of exposure and gender. In utero tobacco exposure may accelerate the progression from experimentation to daily use in girls, result in early tobacco experimentation among boys, and produce higher levels of nicotine dependence among adult smokers.

Adolescent↗

PubMed2003

Smoking impairs muscle recovery from exercise.

Cigarette smoking is a leading cause of many adverse health consequences. Chronic nicotine exposure leads to insulin resistance and may increase the risk of developing non-insulin-dependent diabetes mellitus in young otherwise healthy smokers. To evaluate smoking-induced effects on carbohydrate metabolism, we studied muscle glycogen recovery from exercise in a young healthy population of smokers. The study used 31P-13C NMR spectroscopy to compare muscle glycogen and glucose 6-phosphate levels during recovery in exercised gastrocnemius muscles of randomized cohorts of healthy male smokers (S) and controls (C). Data for the two groups were as follows: S, > or =20 cigarettes/day (n = 8), 24 +/- 2 yr, 173 +/- 3 cm, 70 +/- 4 kg and age- and weight-matched nonsmoking C (n = 10), 23 +/- 1 yr, 175 +/- 3 cm, 67 +/- 3 kg. Subjects performed single-leg toe raises to deplete glycogen to approximately 20 mmol/l, and glycogen resynthesis was measured during the first 4 h of recovery. Plasma samples were assayed for glucose and insulin at rest and during recovery. Test subjects were recruited from the general community surrounding Yale University. Glycogen was depleted to similar levels in the two groups [23.5 +/- 1.2 (S) and 19.1 +/- 1.3 (C) mmol/l]. During the 1st h of recovery, glycogen synthesis rates were similar [13.8 +/- 1.1 (S) and 15.3 +/- 1.3 (C) mmol x l-1 x h-1]. Between hours 1 and 4, glycogen synthesis was impaired in smokers [0.8 +/- 0.2 (S) and 4.5 +/- 0.5 (C) mmol x l-1 x h-1, P = 0.0002] compared with controls. Glucose 6-phosphate was reduced in smokers during hours 1-4 [0.105 +/- 0.006 (S) and 0.217 +/- 0.019 (C) mmol/l, P = 0.0212]. We conclude that cigarette smoking impairs the insulin-dependent portion of muscle recovery from glycogen-depleting exercise. This impairment likely results from a reduction in glucose uptake.

Adult↗

PubMed2003

Naltrexone and nicotine patch smoking cessation: a preliminary study.

This preliminary study evaluated the potential efficacy of 50 mg of opioid antagonist naltrexone or placebo in combination with nicotine replacement therapy for smoking cessation, in a small sample of 32 smokers using one to one and a half packs of cigarettes per day. Addition of naltrexone resulted in an increase in continuous abstinence rates (9/16 for naltrexone vs. 5/16 for placebo). Naltrexone reduced the likelihood of relapse among participants who smoked during the first week of treatment, reduced desire to smoke, and prevented weight gain following smoking cessation. These preliminary results suggest that naltrexone augmentation of nicotine patch therapy using procedures designed to optimize the concurrent use of these two medications may be beneficial for smoking cessation.

Administration, Cutaneous↗