Stephanie S. O’Malley

An Evaluation of μ-Opioid Receptor (OPRM1) as a Predictor of Naltrexone Response in the Treatment of Alcohol Dependence: Results From the Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence (COMBINE) Study

CONTEXT Naltrexone hydrochloride treatment for alcohol dependence works for some individuals but not for everyone. Asn40Asp, a functional polymorphism of the mu-opioid receptor gene (OPRM1), might predict naltrexone response. OBJECTIVE To evaluate whether individuals with alcoholism who are heterozygous (Asp40/Asn40) or homozygous (Asp40/Asp40) for the OPRM1 Asp40 allele respond better to naltrexone. DESIGN Pharmacogenetic analysis conducted between January 1, 2001, and January 31, 2004. SETTING Eleven academic sites in the COMBINE Study. PARTICIPANTS Recently abstinent volunteers who met all 3 of the following conditions: (1) DSM-IV criteria for primary alcohol dependence; (2) participation in the COMBINE Study; and (3) availability of DNA. INTERVENTIONS Alcoholic subjects were treated for 16 weeks with 100 mg of naltrexone hydrochloride (234 Asn40 homozygotes and 67 with at least 1 copy of the Asp40 allele) or placebo (235 Asn40 homozygotes and 68 with at least 1 copy of the Asp40 allele). All participants received medical management (MM) alone or with combined behavioral intervention (CBI). MAIN OUTCOME MEASURES Time trends in percentage of days abstinent, percentage of heavy drinking days, and rates of good clinical outcome. RESULTS Alcoholic subjects with an Asp40 allele receiving MM alone (no CBI) had an increased percentage of days abstinent (P = .07) and a decreased percentage of heavy drinking days (P = .04) if treated with naltrexone vs placebo, while those with the Asn40/Asn40 genotype showed no medication differences. If treated with MM alone and naltrexone, 87.1% of Asp40 carriers had a good clinical outcome, compared with only 54.8% of individuals with the Asn40/Asn40 genotype (odds ratio, 5.75; confidence interval, 1.88-17.54), while, if treated with placebo, 48.6% of Asp40 carriers and 54.0% of individuals with the Asn40/Asn40 genotype had a good clinical outcome (interaction between medication and genotype, P = .005). No gene x medication interactions were observed in those treated with both MM and CBI. CONCLUSIONS These results confirm and extend the observation that the functionally significant OPRM1 Asp40 allele predicts naltrexone treatment response in alcoholic individuals. This relationship might be obscured, however, by other efficacious treatments. OPRM1 genotyping in alcoholic individuals might be useful to assist in selecting treatment options. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00006206.

A preliminary placebo-controlled trial of selegiline hydrochloride for smoking cessation

BACKGROUND Since dopaminergic mechanisms appear to be involved in nicotine dependence, we studied the safety and efficacy of the monoamine oxidase B inhibitor selegiline hydrochloride compared with placebo for smoking cessation in nicotine-dependent cigarette smokers. METHODS Forty subjects with DSM-IV nicotine dependence were randomized to: 1) selegiline hydrochloride (5 mg p.o. twice daily) or 2) placebo in an 8-week trial. Outcome measures included smoking cessation rates, treatment retention, and medication side effects. RESULTS Selegiline hydrochloride increased trial end point (week 8) 7-day point prevalence smoking cessation rates (selegiline hydrochloride, 9/20 [45.0%]; placebo, 3/20 [15.0%], odds ratio = 4.64, 95% CI, 1.02-21.00, p <.05), and smoking cessation rates during the last 4 weeks of the trial (selegiline hydrochloride, 6/20 [30.0%]; placebo, 1/20 [5.0%], odds ratio = 8.14, 95% CI, 0.88-75.48, p =.07) in comparison with placebo. Six-month follow-up 7-day point prevalence smoking cessation rates were reduced compared with trial end point (selegiline hydrochloride, 4/20 [20.0%]; placebo, 1/20 [5.0%], odds ratio = 4.75, 95% CI, 0.48-46.91, p =.18). Treatment retention was similar between drug and placebo groups (p =.13), and selegiline hydrochloride was well tolerated in cigarette smokers. CONCLUSION This preliminary study suggests that selegiline (10 mg/day) is safe for use and enhances smoking cessation rates compared with placebo in nicotine-dependent cigarette smokers.

Sex, GABA, and nicotine: the impact of smoking on cortical GABA levels across the menstrual cycle as measured with proton magnetic resonance spectroscopy.

BACKGROUND Given that nicotine modulates amino acid neurotransmission, we sought to examine the impact of nicotine on cortical gamma-aminobutyric acid (GABA) levels in male and female smokers. METHODS Healthy nicotine-dependent men (n = 10) and women (n = 6) underwent proton magnetic resonance spectroscopy (1H-MRS) to measure occipital cortex GABA concentrations. A subset of the smoking men (n = 5) underwent 1H-MRS scans before and after 48 hours of smoking abstinence, whereas each of the women were scheduled to undergo pre- and postabstinence scans during the follicular and luteal phases of one menstrual cycle. Healthy nonsmoking men (n = 7) and women (n = 13) underwent 1H-MRS for comparison. RESULTS Short-term abstinence had no significant effect on cortical GABA concentrations in either men or women. There was, however, a significant effect of sex, diagnosis (smoker/nonsmoker), and menstrual cycle phase on cortical GABA levels, such that female smokers experienced a significant reduction in cortical GABA levels during the follicular phase and no cyclicity in GABA levels across the menstrual cycle, whereas cortical GABA levels were similar in smoking and nonsmoking men. CONCLUSIONS Taken together with previous 1H-MRS data showing abnormalities in occipital cortex GABA concentrations in several affective disorders, our preliminary finding that nicotine modulation of GABA levels varies by sex provides a further rationale for investigating the impact of nicotine on central GABAergic function as a potential risk factor for women to experience depressive symptoms during smoking cessation.

Naltrexone augmentation of neuroleptic treatment in alcohol abusing patients with schizophrenia

ObjectiveAlcohol abuse in patients with schizophrenia is associated with psychiatric and social complications. While two medications have been approved by the Federal Drug Administration (FDA) for the treatment of alcoholism: disulfiram and naltrexone, no medications have been approved for individuals with alcohol dependence and comorbid schizophrenia. The purpose of this study was to evaluate the efficacy of naltrexone in alcohol-abusing schizophrenic patients.MethodThirty-one patients with schizophrenia and comorbid alcohol abuse or dependence were treated for 12 weeks in an outpatient study using naltrexone or placebo in a randomized, double-blind fashion in addition to their neuroleptic medication. Patients also participated in a weekly therapy using cognitive-behavioral drug relapse prevention strategies combined with skills training. Outcomes included drinking measured by the time line follow-back method, craving using the Tiffany Craving Questionnaire, psychotic symptoms using the Positive and Negative Symptoms Scale (PANSS), side effects and a measures of abnormal involuntary movements.ResultsThere were no significant differences in treatment exposure or medication compliance between groups. Naltrexone treated patients had significantly fewer drinking days, heavy drinking days (>5 drinks) and reported less craving compared to the placebo treated patients. Naltrexone did not affect symptoms of schizophrenia, such as psychosis. The medication was well tolerated and there were no group differences in side effects.ConclusionsThese data suggest that naltrexone may be an effective medication for individuals with comorbid alcohol dependence and schizophrenia. Given the widespread problems associated with alcohol misuse in this population, and the lack of effective pharmacotherapies, these findings represent an exciting clinical development.

Family History of Alcoholism Influences Naltrexone-Induced Reduction in Alcohol Drinking

BACKGROUND The purpose of this study was to examine the interactive effects of family history of alcoholism (FH+, FH-) and naltrexone dose (0, 50, 100 mg/day) on alcohol drinking. METHODS Ninety-two, non-treatment-seeking alcohol-dependent participants received naltrexone daily for 6 days. On the 6th day, they participated in a laboratory paradigm involving exposure to a priming dose of alcohol followed by a 2-hour drinking period in which they made choices between consuming alcoholic drinks and receiving money. RESULTS Total number of drinks consumed during the drinking period was significantly decreased by the 100-mg dose of naltrexone in FH+ drinkers. Secondary analyses in male drinkers (n = 70) indicated that 100 mg of naltrexone significantly decreased drinking in FH+ participants and increased drinking in FH- drinkers. CONCLUSIONS These results suggest that family history of alcoholism might be a significant clinical predictor of response to naltrexone and that FH+ men are more likely to benefit from naltrexone therapy for alcohol drinking.

Naltrexone Alone and With Sertraline for the Treatment of Alcohol Dependence in Alaska Natives and Non-Natives Residing in Rural Settings: A Randomized Controlled Trial

BACKGROUND Access to specialty alcoholism treatment in rural environments is limited and new treatment approaches are needed. The objective was to evaluate the efficacy of naltrexone alone and in combination with sertraline among Alaska Natives and other Alaskans living in rural settings. An exploratory aim examined whether the Asn40Asp polymorphism of the mu-opioid receptor gene (OPRM1) predicted response to naltrexone, as had been reported in Caucasians. METHODS Randomized, controlled trial enrolling 101 Alaskans with alcohol dependence, including 68 American Indians/Alaska Natives. Participants received 16 weeks of either (1) placebo (placebo naltrexone + placebo sertraline), (2) naltrexone monotherapy (50 mg naltrexone + sertraline placebo) and (3) naltrexone + sertraline (100 mg) plus nine sessions of medical management and supportive advice. Primary outcomes included Time to First Heavy Drinking Day and Total Abstinence. RESULTS Naltrexone monotherapy demonstrated significantly higher total abstinence (35%) compared with placebo (12%, p = 0027) and longer, but not statistically different, Time to First Heavy Drinking Day (p = 0.093). On secondary measures, naltrexone compared with placebo demonstrated significant improvements in percent days abstinent (p = 0.024) and drinking-related consequences (p = 0.02). Combined sertraline and naltrexone did not differ from naltrexone alone. The pattern of findings was generally similar for the American Indian/Alaska Native subsample. Naltrexone treatment response was significant within the group of 75 individuals who were homozygous for OPRM1 Asn40 allele. There was a small number of Asp40 carriers, precluding statistical testing of the effect of this allele on response. CONCLUSIONS Naltrexone can be used effectively to treat alcoholism in remote and rural communities, with evidence of benefit for American Indians and Alaska Natives. New models of care incorporating pharmacotherapy could reduce important health disparities related to alcoholism.

The drug effects questionnaire: psychometric support across three drug types.

RationaleThe Drug Effects Questionnaire (DEQ) is widely used in studies of acute subjective response (SR) to a variety of substances, but the format of the DEQ varies widely across studies, and details of its psychometric properties are lacking. Thus, the field would benefit from demonstrating the reliability and validity of the DEQ for use across multiple substances.ObjectiveThe current study evaluated the psychometric properties of several variations of DEQ items, which assessed the extent to which participants (1) feel any substance effect(s), (2) feel high, (3) like the effects, (4) dislike the effects, and (5) want more of the substance using 100-mm visual analog scales.MethodsDEQ data from three placebo-controlled studies were analyzed to examine SR to amphetamine, nicotine, and alcohol. We evaluated the internal structure of the DEQ for use with each substance as well as relationships between scale items, measures of similar constructs, and substance-related behaviors.ResultsResults provided preliminary psychometric support for items assessing each DEQ construct (feel, high, dislike, like, and more).ConclusionsBased on the study results, we identify several common limitations of extant variants of the DEQ and recommend an improved version of the measure. The simplicity and brevity of the DEQ combined with its promising psychometric properties support its use in future SR research across a variety of substances.

Sex differences in availability of β2*-nicotinic acetylcholine receptors in recently abstinent tobacco smokers

CONTEXT Sex differences exist in the reinforcing effects of nicotine, smoking cessation rates, and response to nicotine therapies. Sex differences in availability of nicotinic acetylcholine receptors containing the β(2) subunit (β(2)*-nAChRs) may underlie differential nicotine and tobacco smoking effects and related behaviors in women vs men. OBJECTIVES To examine β(2)*-nAChR availability in male and female smokers vs nonsmokers and to determine associations among β(2)*-nAChR availability, tobacco smoking characteristics, and female sex steroid hormone levels. DESIGN Male (n = 26) and female (n = 28) tobacco smokers participated in an iodide 123-labeled 5-iodo-A-85380 ([(123)I]5-IA) single-photon emission computed tomography (SPECT) imaging session at 7 to 9 days of abstinence. Age-matched male (n = 26) and female (n = 30) nonsmokers participated in a [(123)I]5-IA SPECT imaging session. All participants completed a magnetic resonance imaging study. SETTING Academic imaging center. PARTICIPANTS Tobacco smokers (n = 54) and age- and sex-matched nonsmokers (n = 56). MAIN OUTCOME MEASURE The [(123)I]5-IA SPECT images were converted to equilibrium distribution volumes and were analyzed using regions of interest. RESULTS The β(2)*-nAChR availability was significantly higher in male smokers compared with male nonsmokers in striatum, cortex, and cerebellum, but female smokers did not have higher β(2)*-nAChR availability than female nonsmokers in any region. In women, β(2)*-nAChR availability in the cortex and cerebellum was negatively and significantly correlated with progesterone level on the SPECT imaging day. In female smokers on imaging day, the progesterone level was positively and significantly correlated with depressive symptoms, craving for a cigarette, and nicotine withdrawal. CONCLUSIONS The regulatory effects of nicotine in the brain (ie, tobacco smoking-induced upregulation of β(2)*-nAChRs) seem to be distinctly different between men and women, and female sex steroid hormones likely have a role in this regulation. These findings suggest an underlying neurochemical mechanism for the reported behavioral sex differences. To treat female smokers more effectively, it is critical that nonnicotinic-mediated medications should be explored.

Gender Differences in Alcohol Treatment: An Analysis of Outcome from the COMBINE Study

BACKGROUND Relatively few studies have examined gender differences in the effectiveness of specific behavioral or pharmacologic treatment of alcohol dependence. The aim of this study is to assess whether there were gender differences in treatment outcomes for specific behavioral and medication treatments singly or in combination by conducting a secondary analysis of public access data from the national, multisite NIAAA-sponsored COMBINE study. METHODS The COMBINE study investigated alcohol treatment among 8 groups of patients (378 women, 848 men) who received medical management (MM) with 16 weeks of placebo, naltrexone (100 mg/day), acamprosate (3 g/day), or their combination with or without a specialist-delivered combined behavioral intervention. We examined efficacy measures separately for men and women, followed by an overall analysis that included gender and its interaction with treatment condition in the analyses. These analyses were performed to confirm whether the findings reported in the parent trial were also relevant to women, and to more closely examine secondary outcome variables that were not analyzed previously for gender effects. RESULTS Compared to men, women reported a later age of onset of alcohol dependence by approximately 3 years, were significantly less likely to have had previous alcohol treatment, and drank fewer drinks per drinking day. Otherwise, there were no baseline gender differences in drinking measures. Outcome analyses of 2 primary (percent days abstinent and time to first heavy drinking day) and 2 secondary (good clinical response and percent heavy drinking days) drinking measures yielded the same overall pattern in each gender as that observed in the parent COMBINE study report. That is, only the naltrexone by behavioral intervention interaction reached or approached significance in women as well as in men. There was a naltrexone main effect that was significant in both men and women in reduction in alcohol craving scores with naltrexone-treated subjects reporting lower craving than placebo-treated subjects. CONCLUSIONS This gender-focused analysis found that alcohol-dependent women responded to naltrexone with COMBINEs Medical Management, similar to the alcohol-dependent men, on a wide range of outcome measures. These results suggest that clinicians can feel comfortable prescribing naltrexone for alcohol dependence in both men and women. In this study, it is also notable that fewer women than men reported receiving any alcohol treatment prior to entry into the COMBINE study. Of note, women tend to go to primary health care more frequently than to specialty substance abuse programs for treatment, and so the benefit we confirm for women of the naltrexone and MM combination has practical implications for treating alcohol-dependent women.

Comparison of expired carbon monoxide and plasma cotinine as markers of cigarette abstinence.

The clinical pharmacology of biochemical measures of nicotine exposure has been thoroughly reviewed with regard to usefulness and limitations in detecting abstinence from cigarette smoking. While plasma nicotine concentration measures only acute nicotine exposure, plasma, salivary, and urine cotinine concentrations reflect exposure over an extended period of time. Although, expired carbon monoxide (CO) is frequently used to confirm self reports, it has a relatively short half life, calling into question whether this measure might provide misleading information by exaggerating smoking cessation success rates. To examine this question, we analyzed expired CO, plasma cotinine and self report data collected in a clinical trial in which subjects (N=207) were randomly assigned to gain- or loss-framed messages for smoking cessation in combination with open label sustained-release bupropion (300 mg/day). In examining measurements collected at 6 weeks, 3 and 6 months, results showed that CO significantly overestimated abstinence rates as compared with cotinine, although the discrepancy was less at the later time points. These data suggest that while expired CO is a useful and well-established marker in certain contexts, when testing extended abstinence from smoking with non-nicotine medications, cotinine measurements should be preferred.