The role of biomarkers in alcoholism medication trials

Feasibility of a mail-in, self-administered dried blood spot collection method in national, population-based alcohol surveys in the United States

BACKGROUND AND AIMS

Including a low-intensity blood collection method in population-based alcohol studies would advance our ability to study biological mechanisms related to alcohol. However, the likelihood of participation in such a blood collection method remains understudied. This study's primary aims were to (1) estimate the return rate of mail-in, self-administered dried blood spot (saDBS) samples in national surveys and (2) test correlates of returning a sample.

DESIGN

Re-contact of all eligible participants from two telephone, population-based alcohol surveys followed by χ² tests and multivariate logistic regression analysis.

SETTING

Non-institutionalized US population in all 50 states and Washington, DC.

PARTICIPANTS

Adults aged 18+ who reported drinking at least one alcoholic beverage in the past 12 months (assessed 2017-18). Contact was made with 680 eligible participants, and 257 consented.

MEASUREMENTS

The return rate of saDBS samples was defined as the proportion of returned samples among those who were eligible and contacted. Key correlates examined were gender, age, race/ethnicity and education.

FINDINGS

Among the 680 eligible people contacted, 179 (26.3%) returned a saDBS sample. Blacks [odds ratio (OR) = 0.58, 95% confidence interval (CI) = 0.35-0.95], Latinos (OR = 0.40, 95% CI = 0.23-0.69) and those with a high school education or less (OR = 0.50, 95% CI = 0.31-0.81).

CONCLUSIONS

The likelihood of participating in mail-in, self-administered dried blood spot (saDBS) sampling among drinkers in the US general population appears low, and blacks, Latinos and people with lower levels of education appear less likely to provide a saDBS sample compared with whites and people with higher levels of education.

The influence of caffeine on ethyl glucuronide levels in rat serum and in rat hair

BACKGROUND

Ethanol and caffeine are the most widely used psychoactive substances in the world, with an observed steady increase in the combined consumption of alcohol and caffeine. Specific signs of ethanol-caffeine interactions have been reported both in humans and in animals. The metabolic effects of these interactions have not been fully elucidated. There are no published reports on the influence of caffeine on ethyl glucuronide (EtG) formation. EtG is a direct metabolite of ethanol and is very often used as a biomarker of alcohol consumption. Here, we investigated the influence of caffeine on the formation of EtG in rat plasma and EtG incorporation into the hair.

METHODS

Studies were conducted on three male Wistar rat groups, each receiving either ethanol at 3 g/kg/day, ethanol (at the same dose) with caffeine at 3 mg/kg/day, or caffeine at 3 mg/kg/day for four weeks. EtG and caffeine levels were evaluated in hair and in blood after the last administration.

RESULTS

Blood EtG levels after the administration of ethanol together with caffeine were significantly higher than after the administration of ethanol alone. EtG levels in rat hair in the ethanol-and-caffeine group were also higher than in the ethanol-only group, but the difference was not statistically significant.

CONCLUSION

This study shows the possible effect of ethanol and caffeine co-administration on EtG formation. Caffeine stimulates EtG synthesis resulting in increased blood and, possibly, hair levels of this metabolite. However, the role of these changes in estimating alcohol consumption requires further studies.

Cessation of alcohol consumption decreases rate of nicotine metabolism in male alcohol-dependent smokers

BACKGROUND

Rate of nicotine metabolism is an important factor influencing cigarette smoking behavior, dependence, and efficacy of nicotine replacement therapy. The current study examined the hypothesis that chronic alcohol abuse can accelerate the rate of nicotine metabolism. Nicotine metabolite ratio (NMR, a biomarker for rate of nicotine metabolism) and patterns of nicotine metabolites were assessed at three time points after alcohol cessation.

METHODS

Participants were 22 Caucasian men randomly selected from a sample of 165 smokers entering a 7-week alcohol dependence treatment program in Poland. Data were collected at three time points: baseline (week 1, after acute alcohol detoxification), week 4, and week 7. Urine was analyzed for nicotine and metabolites and used to determine the nicotine metabolite ratio (NMR, a biomarker for rate of nicotine metabolism), and total nicotine equivalents (TNE, a biomarker for total daily nicotine exposure).

RESULTS AND CONCLUSIONS

There was a significant decrease in urine NMR over the 7 weeks after alcohol abstinence (F(2,42)=18.83, p<0.001), indicating a decrease in rate of nicotine metabolism. On average NMR decreased 50.0% from baseline to week 7 (9.6±1.3 vs 4.1±0.6). There was no change in urine TNE across the three sessions, indicating no change daily nicotine intake. The results support the idea that chronic alcohol abuse may increase the rate of nicotine metabolism, which then decreases over time after alcohol cessation. This information may help to inform future smoking cessation interventions in this population.

Focus on alcoholic liver disease: from nosography to treatment

Abusive alcohol intake currently ranks as a major cause of liver disease, and is associated with significant mortality worldwide. Alcoholic liver disease (ALD) generically defines liver abnormalities ranging from liver steatosis to the end-stages of disease such as liver cirrhosis. Information regarding the precise incidence and prevalence of ALD is still limited by a lack of large population-based studies and by the absence of large systematic reviews of all epidemiological data available. However, existing collected data show an overall increase in the number of alcohol abusers and alcohol-related liver disease. The burden exerted on medical systems worldwide is significant, with hospitalization and management costs rising constantly over the years. A great number of all cirrhosis-related deaths in Europe and a significant percentage worldwide are associated with alcohol consumption. The main possible risk factors for ALD are the amount and duration of alcohol abuse, patterns of drinking and the type of alcoholic beverage consumed. However, ALD does not progress to cirrhosis in all patients, therefore a series of additional factors are implicated. Even though insufficiently studied, genetic factors are generally regarded as highly important, and the presence of comorbidities and dietary habits seem to play a role in disease onset and progression. This lack of clear pathophysiological data further translates in the absence of definite treatment for ALD and shall prove challenging in the coming years. In this article, we aimed to briefly review epidemiologic data on the burden of ALD, risk factors, clinical and nosographic as well as therapeutic aspects of this disease. Without attempting to be exhaustive, this short topic highlight emphasizes each point and may serve as a general guidance tool in the complicated literature related to ALD.

Ethanol consumption: how should we measure it? Achieving consilience between human and animal phenotypes

There is only modest overlap in the most common alcohol consumption phenotypes measured in animal studies and those typically studied in humans. To address this issue, we identified a number of alcohol consumption phenotypes of importance to the field that have potential for consilience between human and animal models. These phenotypes can be broken down into three categories: (1) abstinence/the decision to drink or abstain; (2) the actual amount of alcohol consumed; and (3) heavy drinking. A number of suggestions for human and animal researchers are made in order to address these phenotypes and enhance consilience. Laboratory studies of the decision to drink or to abstain are needed in both human and animal research. In human laboratory studies, heavy or binge drinking that meets cut-offs used in epidemiological and clinical studies should be reported. Greater attention to patterns of drinking over time is needed in both animal and human studies. Individual differences pertaining to all consumption phenotypes should be addressed in animal research. Lastly, improved biomarkers need to be developed in future research for use with both humans and animals. Greater precision in estimating blood alcohol levels in the field, together with consistent measurement of breath/blood alcohol levels in human laboratory and animal studies, provides one means of achieving greater consilience of alcohol consumption phenotypes.

Estimating driver risk using alcohol biomarkers, interlock blood alcohol concentration tests and psychometric assessments: initial descriptives

AIM

To identify alcohol biomarker and psychometric measures that relate to drivers' blood alcohol concentration (BAC) patterns from ignition interlock devices (IIDs).

DESIGN, SETTING, PARTICIPANTS, MEASUREMENTS

In Alberta, Canada, 534 drivers, convicted of driving under the influence of alcohol (DUI), installed IIDs and agreed to participate in a research study. IID BAC tests are an established proxy for predicting future DUI convictions. Three risk groups were defined by rates of failed BAC tests. Program entry and follow-up blood samples (n = 302, 171) were used to measure phosphatidyl ethanol (PETH), carbohydrate deficient transferrin (%CDT), gamma glutamyltransferase (GGT) and other biomarkers. Program entry urine (n = 130) was analyzed for ethyl glucuronide (ETG) and ethyl sulphate (ETS). Entry hair samples were tested for fatty acid ethyl esters (FAEE) (n = 92) and ETG (n = 146). Psychometric measures included the DSM-4 Diagnostic Interview Schedule Alcohol Module, Alcohol Use Disorders Identification Test (AUDIT), the time-line follow-back (TLFB), the Drinker Inventory of Consequences (DRINC) and the Temptation and Restraint Inventory (TRI).

FINDINGS

Except for FAEE, all alcohol biomarkers were related significantly to the interlock BAC test profiles; higher marker levels predicted higher rates of interlock BAC test failures. PETH, the strongest with an overall analysis of variance F ratio of 35.5, had significant correlations with all nine of the other alcohol biomarkers and with 16 of 19 psychometric variables. Urine ETG and ETS were correlated strongly with the IID BAC tests.

CONCLUSIONS

The findings suggest that several alcohol biomarkers and assessments could play an important role in the prediction and control of driver alcohol risk when re-licensing.

Naltrexone decreases heavy drinking rates in smoking cessation treatment: an exploratory study

BACKGROUND

There is mixed support for the efficacy of the opioid antagonist naltrexone in the treatment of nicotine dependence. One potential unexplored mechanism underlying naltrexone's effects in smoking cessation may be in its ability to reduce alcohol consumption.

METHODS

Alcohol consumption and liver enzyme levels (aspartate aminotransferase and alanine transaminase) were examined in a sample of 78 nonalcoholic social drinking smokers (34 naltrexone, 44 placebo) enrolled in a double-blind randomized clinical trial of naltrexone in smoking cessation. Naltrexone or placebo began 3 days prior to the quit date (25 mg daily) and continued for 8 weeks (50 mg daily). All participants received nicotine patches and behavioral counseling up through 4 weeks after the quit date.

RESULTS

Naltrexone significantly reduced weekly heavy drinking rates. This effect was associated with greater nausea and pill taking adherence within the naltrexone group. Within heavy drinkers, naltrexone also directionally improved smoking quit rates compared with placebo. Liver enzyme levels did not differ during treatment with naltrexone compared with placebo.

CONCLUSIONS

Naltrexone may reduce the frequency of heavy drinking in nonalcoholics attempting to quit smoking. Further, naltrexone may preferentially improve smoking quit rates within heavy drinkers who smoke, and further investigation in larger sample sizes is warranted.

Assessing comorbid substance use in detained psychiatric patients: issues and instruments for evaluating treatment outcome

This review assesses the issues involved in the selection and treatment of patients comorbid for mental illness and substance misuse being treated in secure psychiatric facilities. It includes those individuals who have a history of offending and whose placement is the result of severe behavioral disturbance. The relevant issues in the assessment and treatment of these patients are reviewed and a battery of tests is suggested on the basis of their usefulness with this population in terms of their brevity, ease of administration, and for their value in planning treatment, providing motivational feedback, and monitoring change. The paucity of assessment tools developed specifically for this patient population is highlighted.

Using topiramate or naltrexone for the treatment of alcohol-dependent patients

BACKGROUND

To compare topiramate versus naltrexone in the treatment of alcohol dependence.

METHODS

A 6-month naturalistic, randomized and open-label, trial of topiramate versus naltrexone, with assessments at enrollment and after 3 and 6 months of treatment. The setting was an outpatient alcohol clinic. One hundred and two alcohol-dependent patients who had been drinking heavily during the past month were included. Two randomized groups were created. In one, naltrexone was used as the therapeutic agent and, in the other, topiramate was chosen as the therapeutic agent. Both groups received psychological relapse prevention therapy. Outcome was measured using tools that assessed alcohol intake, cravings, disability, and quality of life; changes in biomarkers of alcohol intake were also used. With all the data, a secondary composite measure was created in order to assess each patient's global alcohol intake and its consequences.

RESULTS

Both groups showed substantial reduction in their drinking. Naltrexone patients had higher nicotine consumption throughout the study. Topiramate was better at reducing alcohol-related cravings throughout the study. Both treatments had a similar mean cost throughout the study.

CONCLUSIONS

Both topiramate and naltrexone were efficacious in the treatment of alcohol dependence, and the treatment costs were similar. There is a trend for topiramate to be superior to naltrexone on critical measures of drinking; however, the study did not have adequate statistical power to establish this fact.

Association between the Stin2 VNTR polymorphism of the serotonin transporter gene and treatment outcome in alcohol-dependent patients

AIMS

The aim of this study was to investigate the potential association between functional polymorphisms of dopaminergic [dopamine receptor D2 (DRD2), dopamine receptor D3 (DRD3) and dopamine transporter (SLC6A3)] and serotonergic [serotonin 2A receptor (HTR2A) and serotonin transporter (SLC6A4)] genes and treatment outcome in alcohol-dependent patients.

METHODS

A total of 90 Spanish Caucasian alcohol-dependent outpatients (ICD-10 criteria) were enrolled in the study. The association between genotypes and drinking outcomes was measured over 6 months of treatment. Biomarkers of alcohol consumption, as well as alcohol consumption and its consequences, craving, disability and quality of life, were assessed. Based on those measures, we created a composite secondary measure to globally assess treatment outcome in alcoholism.

RESULTS

No association was found between DRD2, DRD3, SLC6A3 or HTR2A gene variants and treatment outcome. However, SLC6A4 STin2 12/12 carriers showed poor 6-month time point treatment outcome [32.8% in the good outcome group versus 64.0% in the poor outcome group, chi(2) (df) = 7.20 (1), corrected P = 0.042, OR (95% CI) = 0.27 (0.10-0.72)]. Nevertheless, independent analysis of each treatment group reveals that the excess of 12/12 carriers in the poor outcome group was only found in the naltrexone-treated group [24.1% versus 64.7% chi(2) (df) = 7.41 (1), corrected P = 0.042, OR (95% CI) = 0.17 (0.05-0.64)]. In the whole sample, the L-10 repeats haplotype (5-HTTLPR-STin2 VNTR) is associated with good outcome (LRT = 3.88, df = 1, P = 0.049).

CONCLUSIONS

Our findings suggest that functional polymorphism of the SLC6A4 gene may have an influence on treatment outcome in alcohol-dependent patients.

The status of naltrexone in the treatment of alcohol dependence: specific effects on heavy drinking

BACKGROUND

In almost 2 decades of naltrexone research for treating alcoholism, there have been 29 published randomized placebo-controlled trials of opioid antagonists, primarily naltrexone, for the treatment of alcohol dependence. The present review builds on prior systematic reviews while maximizing the number of included studies to date, for the purpose of resolving inconsistencies in naltrexone's reported efficacy across trials. Clinical trial results in this article are evaluated by the type of outcome measure used to determine naltrexone's treatment advantage, that is, measures related to reducing heavy drinking versus those related to increasing abstinence.

METHODS

We conducted a Medline search to identify double-blind studies from 1990 to the present (2006) that evaluated the use of anopiate antagonist for the treatment of alcohol dependence. There were 29 studies identified, representing 5997 alcohol-dependent patients, which met our study inclusion criteria for this review. Studies were evaluated in this review on 4 prespecified drinking outcomes-2 related to "any drinking" and 2 related to "heavy or excessive drinking."

RESULTS

In the treatment of alcohol dependence, we found that 19 (70%) of 27 clinical trials that measured reductions in "heavy or excessive drinking" demonstrated an advantage for prescribing naltrexone over placebo, whereas only 9 (36%) of 25 clinical trials that measured abstinence or "any drinking" found an advantage for medication over placebo.

CONCLUSION

The majority of double-blind clinical trials in the literature favored prescribing naltrexone for alcohol dependence to reduce heavy drinking. This finding is consistent with our understanding of naltrexone's mechanism of action of decreasing excessive drinking by reducing the reward associated with drinking alcohol. Thus, we conclude that outcome measures related to heavy or excessive drinking are most relevant to defining naltrexone's therapeutic effects. Factors influencing naltrexone response (treatment adherence and distinct patient subgroups) are also discussed.

Factors Affecting %CDT Status at Entry Into a Multisite Clinical Treatment Trial: Experience from the COMBINE Study

BACKGROUND

Carbohydrate-deficient transferrin (CDT) occurs as a higher percentage of normal transferrin (%CDT) in heavy drinkers. %CDT is used as a marker of both alcohol use disorder severity and treatment outcome both clinically and in treatment trials. Nevertheless, little is known about the parameters that predict which patients are %CDT positives at treatment entry. These parameters might include level of drinking, days of abstinence before testing, and severity of alcohol dependence before evaluation.

METHODS

%CDT levels were collected before randomization from participants of the COMBINE Study, a large federally sponsored multisite clinical trial evaluating medications and behavioral therapies in alcohol-dependent outpatients. %CDT (assayed in a central laboratory) was available in 1,193 individuals for whom drinking history in the 30 days before testing and measures of alcoholism severity were documented. The effects of drinking history and alcohol severity were evaluated for prediction of a %CDT-positive test status.

RESULTS

Less percent days abstinent (PDA) and more drinks per drinking day (DDD) were predictive of higher rates of %CDT-positive patients (maximum 67%). Up to 14 days of continuous abstinence before testing did not appear to significantly affect %CDT status. Rates of %CDT positives remained reasonably steady up to about 40% PDA. Years of drinking at dependence levels had an unexpected negative impact on %CDT-positive rates while previous treatment had a small but positive impact of %CDT-positive rates. ADS and DrInC scores had no predictive value over and above recent drinking amounts on %CDT status.

CONCLUSIONS

%CDT is more likely to be positive in those who have more days of drinking and to a lesser degree in those who drink more per drinking day. It can remain positive even in those alcoholic subjects who stop drinking many days before testing. Alcoholic subjects with more treatment experiences appear to have a marginally higher %CDT-positive rate.

Alanine Aminopeptidase Activity in Urine: A New Marker of Chronic Alcohol Abuse?

BACKGROUND

The purpose of this study was to evaluate the activity of urinary alanine aminopeptidase (AAP), the enzyme released from the brush border membranes of renal proximal tubules, as a new biological marker of chronic alcohol abuse.

METHODS

The AAP activity was assayed and compared between a group of 76 alcoholics undergoing detoxification and a group of 37 alcoholics abstaining from alcohol for at least 6 weeks. In all patients, the enzyme activity was measured both in untreated urine (uAAP) and after removal of endogenous AAP inhibitors by molecular filtration on Sephadex (eAAP).

RESULTS

There was a correlation between the uAAP and eAAP activities in both groups of patients (r = 0.61 and r = 0.81 in abstinent alcoholics and in alcoholics undergoing detoxification, respectively), and both the uAAP activity and the eAAP activity were significantly and markedly higher in alcoholics being detoxified than in their abstinent counterparts. As revealed by receiver operating characteristic analysis, the discriminative power of the eAAP activity assay was higher than that of the uAAP activity assay. The area under the corresponding receiver operating characteristic curves was 0.84 +/- 0.04 and 0.78 +/- 0.05 (mean +/- SE), respectively.

CONCLUSIONS

The results of this study demonstrate that the assays of urinary AAP activity, which relate to the nephrotoxic effects of alcohol abuse, could be a valuable complement to the other presently used markers of chronic alcohol abuse that are generally based on ethanol hepatotoxicity. Compared with the uAAP activity test, the eAAP activity test is of clear diagnostic advantage.

COMPARISON OF SERUM FATTY ACID ETHYL ESTERS AND URINARY 5-HYDROXYTRYPTOPHOL AS BIOCHEMICAL MARKERS OF RECENT ETHANOL CONSUMPTION

AIMS

To examine the effects of an acute dose of ethanol on serum fatty acid ethyl esters (FAEEs) concentration and urinary 5-hydroxytryptophol (5-HTOL)/5-hydroxyindole-3-acetic acid (5-HIAA) ratio.

METHODS

Sixteen (14 male, 2 female) heavy alcohol drinkers were tested in a single, 2-day long session. Six participants received 1.5 g/l of ethanol/l of body water (approximately 0.75 g/kg of body weight, low dose group: LD) and 10 participants received 2.0 g/l of ethanol ( approximately 1.0 g/kg of body weight, high dose group: HD) in four divided doses every 20 min. Blood, urine, and breath samples were collected repeatedly over 36 h following the ingestion of ethanol and were analyzed for the presence of FAEE, 5-HTOL/5-HIAA, and ethanol, respectively. Serum gamma-glutamyltransferase (GGT), a marker of chronic ethanol use, was also included.

RESULTS

The breath ethanol level peaked approximately 1 h after the last dose, at 95 and 120 mg/dl for the LD and HD groups, respectively. The mean ratio of urinary 5-HTOL/5-HIAA was significantly elevated 5 and 9 h after ethanol administration, but returned to baseline 13 h after ethanol administration. This ratio was twice as high for the HD group compared with the LD group. Serum levels of FAEEs were significantly elevated at 5 h, but not 13 h after ethanol administration. There were no time-dependent changes in serum GGT levels.

CONCLUSIONS

Measuring the levels of FAEE and 5-HTOL/5-HIAA ratio provides a convenient method to detect recent, particularly binge-type, ethanol use, but these measures may have limited applicability in detecting ethanol use in traditional clinical trial settings.

The Effectiveness of Telephone-Based Continuing Care in the Clinical Management of Alcohol and Cocaine Use Disorders: 12-Month Outcomes

This study of continuing care for substance dependent patients compared a telephone-based monitoring and brief counseling intervention (TEL) with 2 face-to-face interventions, relapse prevention (RP) and standard 12-step group counseling (STND). The participants were graduates of intensive outpatient programs who had current dependence on alcohol and/or cocaine. Self-report, collateral, and biological measures of alcohol and cocaine use were obtained over a 12-month follow-up. The treatment groups did not differ on abstinence-related outcomes in the complete sample (N = 359) or on cocaine use outcomes in participants with cocaine dependence (n = 268). However, in participants with alcohol dependence only (n = 91), TEL produced better alcohol use outcomes than STND on all measures examined and better outcomes than RP on some of the measures.

Efficacy and safety of naltrexone and acamprosate in the treatment of alcohol dependence: a systematic review

AIMS

To ascertain the efficacy and safety of naltrexone and acamprosate in the treatment of alcohol dependence.

METHODS

Systematic review of the literature (1990-2002) and meta-analysis of full published randomized and controlled clinical trials assessing acamprosate or naltrexone therapy in alcohol dependence. Estimates of effect were calculated according to the fixed-effects model.

MEASUREMENTS

Relapse and abstinence rates, cumulative abstinence duration and treatment compliance were considered as primary outcomes. Findings Thirty-three studies met the inclusion criteria. Acamprosate was associated with a significant improvement in abstinence rate [odds ratio (OR): 1.88 (1.57, 2.25), P < 0.001] and days of cumulative abstinence [WMD: 26.55 (17.56, 36.54]. Short-term administration of naltrexone reduced the relapse rate significantly [OR: 0.62 (0.52, 0.75), P < 0.001], but was not associated with a significant modification in the abstinence rate [OR: 1.26 (0.97,1.64), P = 0.08]. There were insufficient data to ascertain naltrexone's efficacy over more prolonged periods. Acamprosate had a good safety pattern and was associated with a significant improvement in treatment compliance [OR: 1.29 (1.13,1.47), P < 0.001]. Naltrexone's side effects were more numerous, yet the drug was nevertheless tolerated acceptably without being associated with a lower adherence to treatment (OR: 0.94 (0.80, 1.1), P = 0.5). However, overall compliance was relatively low with both medications.

CONCLUSIONS

Both acamprosate and naltrexone are effective as adjuvant therapies for alcohol dependence in adults. Acamprosate appears to be especially useful in a therapeutic approach targeted at achieving abstinence, whereas naltrexone seems more indicated in programmes geared to controlled consumption. Both drugs are safe and acceptably tolerated but issues of compliance need to be addressed adequately to assure their usefulness in clinical practice.

Recommendations on Use of Biomarkers in Alcoholism Treatment Trials

BACKGROUND

Biochemical markers of heavy drinking are playing increasingly prominent roles in alcohol treatment efficacy studies, especially in those designed to evaluate medications. Among these roles are serving as inclusion or exclusion criteria for research participants, corroboration of self-report of drinking status, assessment of the safety of the agent being evaluated, and determination of treatment outcome.

METHODS

Recent alcohol medication development trials that included biomarker information were reviewed and critiqued from the perspectives of how biomarker measures were used and how findings on them were reported.

RESULTS

Although generally the application of biomarkers as inclusion criteria is not recommended, they may aid in exclusion of potential subjects (e.g., elevated liver function measures in trials of agents that could result in liver damage). Biomarkers are most commonly used as indicators of outcome, usually serving as secondary outcome variables. The relationship of outcome findings on biomarker and self-report measures is positive, but only moderate. As used to date, biomarkers of drinking tend to be less sensitive than well-standardized and properly administered self-report measures. Nevertheless, they do provide a useful, unique source of information on drinking status.

CONCLUSIONS

The contribution of biomarkers to alcoholism clinical research would be enhanced if certain design strategies were incorporated into their application and if critical information were included in the research publication. This article offers a series of recommendations to improve on their use in a research context.