George A. Kenna

Typologies of Alcohol Dependence. From Jellinek to Genetics and Beyond

The goal of typology research is to identify subtypes of alcohol dependent (AD) patients sharing fundamental characteristics and try to match each subtype, with the most precise treatment strategy. This review provides a comprehensive history of the literature on alcohol dependent subtypes starting from the earliest attempt made by Jellinek. The binary models identified most closely with Cloninger and Babor as well as the successively more complex classifications are discussed. Typology classification potentially useful in guiding the treatment of AD patients, especially in the case of the serotonergic medications. Contrasting data suggests that other factors could influence the response to a medication and/or that more complex typologies should be identified. In summary, typology models may assist in the ascertainment criteria for clinical trials performed in behavioral and pharmacotherapeutic interventions. Greater emphasis, however, must be made to more clearly delineate this field of research, while moving toward more standardized typologies.

Ghrelin system in alcohol‐dependent subjects: role of plasma ghrelin levels in alcohol drinking and craving

Animal studies suggest that the gut‐brain peptide ghrelin plays an important role in the neurobiology of alcohol dependence (AD). Human studies show an effect of alcohol on ghrelin levels and a correlation between ghrelin levels and alcohol craving in alcoholics.

Association of the 5-HTT gene-linked promoter region (5-HTTLPR) polymorphism with psychiatric disorders: review of psychopathology and pharmacotherapy.

Serotonin (5-HT) regulates important biological and psychological processes including mood, and may be associated with the development of several psychiatric disorders. An association between psychopathology and genes that regulate 5-HT neurotransmission is a robust area of research. Identification of the genes responsible for the predisposition, development, and pharmacological response of various psychiatric disorders is crucial to the advancement of our understanding of their underlying neurobiology. This review highlights research investigating 5-HT transporter (5-HTTLPR) polymorphism, because studies investigating the impact of the 5-HTTLPR polymorphism have demonstrated significant associations with many psychiatric disorders. Decreased transcriptional activity of the S allele (“risk allele”) may be associated with a heightened amygdala response leading to anxiety-related personality traits, major depressive disorder, suicide attempts, and bipolar disorder. By contrast, increased transcriptional activity of the L allele is considered protective for depression but is also associated with completed suicide, nicotine dependence, and attention deficit hyperactivity disorder. For some disorders, such as post-traumatic stress disorder and major depressive disorder, the research suggests that treatment response may vary by allele (such as an enhanced response to serotonin specific reuptake inhibitors in patients with major depressive disorder and post-traumatic stress disorder with L alleles), and for alcohol dependence, the association and treatment for S or L alleles may vary with alcoholic subtype. While some studies suggest that 5-HTTLPR polymorphism can moderate the response to pharmacotherapy, the association between 5-HTTLPR alleles and therapeutic outcomes is inconsistent. The discovery of triallelic 5-HTTLPR alleles (LA/LG/S) may help to explain some of the conflicting results of many past association studies, while concurrently providing more meaningful data in the future. Studies assessing 5-HTTLPR as the solitary genetic factor contributing to the etiology of psychiatric disorders continue to face the challenges of statistically small effect sizes and limited replication.

Association of antipsychotic and antidepressant drugs with Q-T interval prolongation

PURPOSE The association of antipsychotic and antidepressant drugs with Q-T interval prolongation is reviewed. SUMMARY Prolongation of the Q-T interval can be of particular concern to practitioners when prescribing antidepressants and antipsychotics. Patients may be at a greater risk for developing fatal arrhythmias when taking many of these drugs. In general, antipsychotics cause Q-T interval prolongation at a higher rate than do antidepressants. The typical antipsychotics thioridazine, pimozide, and intravenous haloperidol all have the highest potential for Q-T interval prolongation. The tricyclic antidepressants have a higher rate of Q-T interval prolongation than do selective serotonin-reuptake inhibitors (SSRIs), particularly at higher concentrations and in cases of overdose. In addition, nonpharmacologic risk factors such as existing heart disease, female sex, electrolyte abnormalities, hepatic insufficiency, and stimulant drug abuse contribute to the risk for developing these arrhythmias, as do pharmacologic factors such as multidrug therapy and high dosages of drugs known to prolong the Q-T interval. Risk factors may be identified in the patients history and demographic information. However, all pharmacists may not have this information readily available to them. CONCLUSION Antipsychotics cause Q-Tc interval prolongation at a higher rate than do antidepressants, and the typical anti-psychotics thioridazine, pimozide, and i.v. haloperidol all have the highest potential for Q-Tc interval prolongation. Tricyclic antidepressants have a higher rate of Q-Tc interval prolongation than do the SSRIs, particularly at higher concentrations and in overdose situations. The frequency of adverse events associated with drug-induced Q-T interval prolongation is unknown.

Current and Promising Pharmacotherapies, and Novel Research Target Areas in the Treatment of Alcohol Dependence: A Review

Harmful alcohol use is a risk factor in more than 60 diseases and injuries resulting in approximately 2.5 million deaths per year worldwide. In the United States (US) and Europe, there are only a few medications approved for alcohol dependence (AD) however, these medications have only been moderately effective and there is a crucial need for more effective treatments. This review briefly summarizes research on currently approved medications for AD, as well as promising medications like topiramate, baclofen and ondansetron. Topiramate is likely the most promising new treatment for AD, however, further research is needed to determine the optimal dose and appropriate length of treatment. Baclofen, a GABA(B) agonist, is a promising medication as a treatment for AD, especially for patients with AD and severe liver disease. Ondansetron has shown promising results as a potential medication for AD, but only within a certain subtype of individuals. This review also discusses more recent findings on other potential pharmacotherapies for AD, such as serotonin-specific reuptake inhibitors (SSRIs; i.e. sertraline), aripiprazole and prazosin, as well as on some examples of other potentially interesting new neuropharmacological targets (i.e. cannabinoid receptors, CRF, NPY, ghrelin). Finally, the present review also discusses the attempts to personalize medication for AD treatment by alcohol typology and pharmacogenetics.

Intravenous Ghrelin Administration Increases Alcohol Craving in Alcohol-Dependent Heavy Drinkers: A Preliminary Investigation

BACKGROUND There is a need to identify novel pharmacologic targets to treat alcoholism. Animal and human studies suggest a role for ghrelin in the neurobiology of alcohol dependence and craving. Here, we were the first to test the hypothesis that intravenous administration of exogenous ghrelin acutely increases alcohol craving. METHODS This was a double-blind, placebo-controlled human laboratory proof-of-concept study. Nontreatment-seeking, alcohol-dependent, heavy-drinking individuals were randomized to receive intravenous ghrelin 1 mcg/kg, 3 mcg/kg or 0 mcg/kg (placebo), followed by a cue-reactivity procedure, during which participants were exposed to neutral (juice) and alcohol cues. The primary outcome variable was the increase in alcohol craving (also called urge) for alcohol, assessed by the Alcohol Visual Analogue Scale. RESULTS Out of 103 screenings, 45 individuals received the study drug. Repeated measures of analysis of covariance revealed a group effect across ghrelin doses in increasing alcohol craving (p < .05). A dose-specific examination revealed a significant effect of ghrelin 3 mcg/kg versus placebo in increasing alcohol craving (p < .05) with a large effect size (d = .94). By contrast, no significant ghrelin effect was found in increasing either urge to drink juice or food craving (p = ns). No significant differences in side effects were found (p = ns). CONCLUSIONS Intravenous administration of exogenous ghrelin increased alcohol craving in alcohol-dependent heavy-drinking individuals. Although the small sample requires confirmatory studies, these findings provide preliminary evidence that ghrelin may play a role in the neurobiology of alcohol craving, thus demonstrating a novel pharmacologic target for treatment.

Pharmacotherapy of Dual Substance Abuse and Dependence

The US FDA has approved a limited number of treatments for alcohol, nicotine and opioid dependence; however, no treatments for other abused drugs such as marijuana, cocaine or methamphetamine are approved. This review focuses on research into drug pharmacotherapies, particularly single-drug therapies, for substance abuse and dependence contributing to the most important dual substance use disorders (SUDs). Given the implications of poly-substance abuse, it is essential that clinicians and researchers be aware of potential pharmacotherapies for the treatment of dual SUDs.A substantial number of patients abuse more than one drug concurrently, complicating the treatment of SUD and leaving clinicians with few FDA-approved drug options for their patients. In this era of evidence-based medicine, such patients are typically treated with therapeutically proven medications, but in ways that are outside the scope of a drug’s original indication by the FDA. Such ‘off-label’ prescribing has become an important therapeutic strategy for practitioners seeking treatments for other diseases in subpopulations such as paediatrics and gerontology or for medical conditions such as oncology or mental illness. Similarly, the information that most clinicians use to make their decisions for treating patients abusing multiple drugs stems from trials treating a single SUD, anecdotal experiences from their own practice or that of their colleagues, or single-case studies reported in the literature.The existing evidence suggests there are few treatments for SUDs that confer significant reductions in substance use across a broad patient population. Moreover, even fewer clinical efficacy trials have been conducted that provide evidence of therapeutic benefit for these drugs. Recognising the difficulty in making the proper drug choice for facilitating maximum treatment success, this review highlights the single drugs or drug combinations that show some potential for treating dual SUDs. This review finds strongest support for the use of disulfiram for treatment of alcohol and cocaine dependence (with or without concomitant methadone maintenance), baclofen for alcohol and cocaine dependence (but not opioid-dependent cocaine users), tiagabine for cocaine dependence in methadone-maintained patients, and topiramate for alcohol, nicotine and cocaine dependence. While ondansetron and olanzapine show some efficacy in treating alcohol and cocaine dependence, more research is needed to better delineate the subpopulation in which these drugs may provide their maximum effect.

Risk factors for alcohol and other drug use by healthcare professionals

BackgroundGiven the increasingly stressful environment due to manpower shortages in the healthcare system in general, substance induced impairment among some healthcare professions is anticipated to grow. Though recent studies suggest that the prevalence of substance abuse is no higher in healthcare professionals (HPs) than the general population, given the responsibility to the public, any impairment could place the public at increased risk for errors. Few studies have ever reported predictors or risk factors for alcohol and other drug use (AOD) across a sample of HPs.MethodsThe study used a cross-sectional, descriptive self-report survey in a small northeastern state. A 7-page survey was mailed to a stratified random sample of 697 dentists, nurses, pharmacists and physicians registered in a northeastern state. The main outcome measures were demographic characteristics, lifetime, past year and past month prevalence of AOD use, the frequency of use, drug related dysfunctions, drug misuse and abuse potential. Six contacts during the summer of 2002 resulted in a 68.7% response rate (479/697).ResultsRisk factors contributing to any reported past year AOD use, as well as significant (defined as the amount of AOD use by the top 25% of respondents) past year AOD use by HPs were examined using logistic regression. Risk factors of any self-reported past year AOD use included moderate or more frequency of alcohol use, being in situations when offered AODs, feeling immune to the addictive effects of drugs (pharmaceutical invincibility) and socializing with substance abusers. Risk factors of significant past year AOD use were HPs with younger licensees, a moderate pattern of alcohol use and not socializing with substance abusers.ConclusionNational and state organizations need to develop policies that focus on prevention, treatment, and rehabilitation of alcohol and other drug-using healthcare professionals. The results of this study may help to delineate the characteristics of HPs abusing drugs, leading to the development of more effective policies designed to protect the public, and move toward more tailored and effective intervention strategies for HPs.

Baclofen promotes alcohol abstinence in alcohol dependent cirrhotic patients with hepatitis C virus (HCV) infection

Hepatitis C virus (HCV) and alcoholic liver disease (ALD), either alone or in combination, count for more than two thirds of all liver diseases in the Western world. There is no safe level of drinking in HCV-infected patients and the most effective goal for these patients is total abstinence. Baclofen, a GABA(B) receptor agonist, represents a promising pharmacotherapy for alcohol dependence (AD). Previously, we performed a randomized clinical trial (RCT), which demonstrated the safety and efficacy of baclofen in patients affected by AD and cirrhosis. The goal of this post-hoc analysis was to explore baclofens effect in a subgroup of alcohol-dependent HCV-infected cirrhotic patients. Any patient with HCV infection was selected for this analysis. Among the 84 subjects randomized in the main trial, 24 alcohol-dependent cirrhotic patients had a HCV infection; 12 received baclofen 10mg t.i.d. and 12 received placebo for 12-weeks. With respect to the placebo group (3/12, 25.0%), a significantly higher number of patients who achieved and maintained total alcohol abstinence was found in the baclofen group (10/12, 83.3%; p=0.0123). Furthermore, in the baclofen group, compared to placebo, there was a significantly higher increase in albumin values from baseline (p=0.0132) and a trend toward a significant reduction in INR levels from baseline (p=0.0716). In conclusion, baclofen was safe and significantly more effective than placebo in promoting alcohol abstinence, and improving some Liver Function Tests (LFTs) (i.e. albumin, INR) in alcohol-dependent HCV-infected cirrhotic patients. Baclofen may represent a clinically relevant alcohol pharmacotherapy for these patients.

A human laboratory pilot study with baclofen in alcoholic individuals.

Preclinical and clinical studies show that the GABA(B) receptor agonist baclofen may represent a pharmacotherapy for alcohol dependence (AD). However, the mechanisms by which baclofen affects drinking are not well characterized; thus this pilot study investigated possible baclofens biobehavioral mechanisms. The design was a double-blind controlled randomized human laboratory pilot study. Fourteen non-treatment seeking alcohol-dependent heavy drinking subjects received either baclofen 10mg t.i.d. or an active placebo (cyproheptadine 2mg t.i.d., to control for sedation) for a 7-day period. At day 8, participants performed an alcohol cue-reactivity (CR) followed by an alcohol self-administration (ASA). Additionally, we explored possible moderators that might guide future larger studies, i.e. anxiety, family history and onset of alcoholism, and D4 dopamine receptor (DRD4) and 5-HTTLPR polymorphisms. The main results were a significant effect of baclofen for increasing stimulation (p=.001) and sedation (p<.01). Furthermore, when drinking during the ASA and the 2 days before was analyzed as a composite variable, there was a significant effect of baclofen to reduce alcohol consumption (p<.01). As for the exploratory analyses, baclofens effects to increase alcohol sedation and to reduce alcohol consumption were limited to those individuals with DRD4 ≥7 repeats (DRD4L). Yet, baclofens effects on alcohol consumption were also moderated by 5-HTTLPR LL genotype. In conclusion, baclofens ability to reduce alcohol drinking may be related to its effects on the biphasic effects of alcohol, but larger studies are needed to confirm these preliminary findings.