Patient‐treatment matching with anti‐craving medications in alcohol‐dependent patients: A review on phenotypic, endophenotypic and genetic indicators

Reward and relief dimensions of temptation to drink: construct validity and role in predicting differential benefit from acamprosate and naltrexone

Researchers have sought to distinguish between individuals whose alcohol use disorder (AUD) is maintained by drinking to relieve negative affect ('relief drinkers') and those whose AUD is maintained by the rewarding effects of alcohol ('reward drinkers'). As an opioid receptor antagonist, naltrexone may be particularly effective for reward drinkers. Acamprosate, which has been shown to down-regulate the glutamatergic system, may be particularly effective for relief drinkers. This study sought to replicate and extend prior work (PREDICT study; Glöckner-Rist et al. ) by examining dimensions of reward and relief temptation to drink and subtypes of individuals with distinct patterns of reward/relief temptation. We utilized data from two randomized clinical trials for AUD (Project MATCH, n = 1726 and COMBINE study, n = 1383). We also tested whether classes of reward/relief temptation would predict differential response to naltrexone and acamprosate in COMBINE. Results replicated prior work by identifying reward and relief temptation factors, which had excellent reliability and construct validity. Using factor mixture modeling, we identified five distinct classes of reward/relief temptation that replicated across studies. In COMBINE, we found a significant class-by-acamprosate interaction effect. Among those most likely classified in the high relief/moderate reward temptation class, individuals had better drinking outcomes if assigned to acamprosate versus placebo. We did not find a significant class-by-naltrexone interaction effect. Our study questions the orthogonal classification of drinkers into only two types (reward or relief drinkers) and adds to the body of research on moderators of acamprosate, which may inform clinical decision making in the treatment of AUD.

Heroin-assisted treatment in the Netherlands: History, findings, and international context

This monograph describes the history, findings and international context of heroin-assisted treatment (HAT) in the Netherlands. The monograph consists of (1) a short introduction and seven paragraphs describing the following aspects of HAT in the Netherlands: (2) history of HAT studies and implementation of routine HAT in the Netherlands; (3) main findings on efficacy, safety and cost-effectiveness from the two randomized controlled HAT trials in the Netherlands; (4) new findings from a large cohort study on the effectiveness of HAT in routine clinical practice in the Netherlands; (5) unique data on the patient's perspective of HAT; (6) data on the pharmacological and pharmaceutical basis for HAT in the Netherlands; (7) description of the registration process; and (8) account of the international context of HAT. Together, these data show that HAT can now be considered a safe and proven-effective intervention for the treatment of chronic, treatment-resistant heroin dependent patients.

Predicting the effect of naltrexone and acamprosate in alcohol-dependent patients using genetic indicators

Acamprosate and naltrexone are effective medications in the treatment of alcoholism. However, effect sizes are modest. Pharmacogenomics may improve patient-treatment-matching and effect sizes. It is hypothesized that naltrexone exerts its effect through genetic characteristics associated with the dopaminergic/opioidergic positive reinforcement system, whereas acamprosate works through the glutamatergic/GABAergic negative reinforcement system. Alcohol-dependent subjects were randomly assigned to either acamprosate or naltrexone. Subjects participated in a cue-exposure experiment at the day before and at the last day of medication. Reductions in cue-induced craving and physiological cue reactivity were measured. Differential effects of naltrexone and acamprosate on these outcomes were tested for different polymorphisms of the opioid, dopamine, glutamate and GABA-receptors. Significant matching effects were found for polymorphisms at the DRD2, GABRA6 and GABRB2 gene. In addition, a trend was found for the OPRM1 polymorphism. This provides evidence for the matching potential of genotypes. It is expected that more effective treatments can be offered when genetic information is used in patient-treatment-matching.

The role of self-reported impulsivity and reward sensitivity versus neurocognitive measures of disinhibition and decision-making in the prediction of relapse in pathological gamblers

BACKGROUND

Disinhibition and decision-making skills play an important role in theories on the cause and outcome of addictive behaviors such as substance use disorders and pathological gambling. In recent studies, both disinhibition and disadvantageous decision-making strategies, as measured by neurocognitive tests, have been found to influence the course of substance use disorders. Research on factors affecting relapse in pathological gambling is scarce.

METHOD

This study investigated the effect of both self-reported impulsivity and reward sensitivity, and neurocognitively assessed disinhibition and decision-making under conflicting contingencies, on relapse in a group of 46 pathological gamblers.

RESULTS

Logistic regression analysis indicated that longer duration of the disorder and neurocognitive indicators of disinhibition (Stop Signal Reaction Time) and decision-making (Card Playing Task) were significant predictors of relapse (explaining 53% of the variance in relapse), whereas self-reported impulsivity and reward sensitivity did not significantly predict relapse. Overall classification accuracy was 76%, with a positive classification accuracy of 76% and a negative classification accuracy of 75%.

CONCLUSIONS

Duration of the disorder and neurocognitive measures of disinhibition and decision-making are powerful predictors of relapse in pathological gambling. The results suggest that endophenotypical neurocognitive characteristics are more promising in the prediction of relapse in pathological gambling than phenotypical personality characteristics. Neurocognitive predictors may be useful to guide treatment planning of follow-up contacts and booster sessions.

Measuring craving: an attempt to connect subjective craving with cue reactivity

BACKGROUND

Better insight into craving may contribute to the development of more efficient relapse prevention strategies. Inconsistent findings on the relation between craving and relapse may be due to difficulties in the measurement of craving. These difficulties are accounted for by 3 interrelated problems: lack of consensus regarding the definition of craving, the use of different time frames (craving now vs craving in the past), and lack of concordance between self-reported craving and psychophysiological measures of cue reactivity. The aim of this study is to develop and validate a new self-report questionnaire for the assessment of the core aspects of craving, taking into account different time frames and emphasizing the psychophysiological aspects of craving. It is hypothesized that this questionnaire will show higher concordance with measures of cue reactivity than existing self-report craving questionnaires.

METHODS

Based on a semantic mapping sentence, a 24-item self-report questionnaire was developed: the Jellinek Alcohol Craving Questionnaire (JACQ). The questionnaire was tested in 2 samples of treatment-seeking alcohol-dependent patients (sample A, n = 251; sample B, n = 48). Psychometric properties were examined in sample A and cross-validated in sample B. The associations with psychophysiological and neuroendocrine measures of cue reactivity were studied in sample B.

RESULTS

The JACQ consists of 1 dimension with the following 4 aspects: (1) emotional urge, (2) physical sensations, (3) temptation to drink, and (4) uncontrolled thoughts. All (sub)scales had a good internal consistency (alpha = 0.77-0.95) and were highly intercorrelated (r = 0.57-0.86). Craving-past correlated low with craving-now (r = 0.32). Craving-now (sub)scales showed a moderate association with heart rate (0.46-0.49), but not with respiration rate, skin conductance, or cortisol production in saliva following cue exposure. In contrast, craving-past (sub)scales showed a moderate association with cortisol production in saliva (0.15-0.42) following cue exposure. Remarkably, the physical symptoms scale did not show stronger association with psychophysiological and neuroendocrine measures than the other subscales.

CONCLUSIONS

The JACQ reliably measures 1 dimension including 4 aspects of craving for distinct time frames. Despite the presence of a special subscale for physical sensations, only moderate relationships were found between self-reported craving and biological indicators of cue reactivity. These findings suggest individual differences between alcoholics in the detection and/or reporting of cue-related psychophysiological signs as indicators of cue reactivity. Further research should focus on the nature of these individual differences. In addition, more research is needed on the relative predictive validity of subjective phenotypic indicators of craving (such as self-reported craving) versus objective endophenotypic indicators of craving (such as physiological measures of cue reactivity) for example in the prediction of relapse.

Pharmacotherapy for alcohol dependence: anticraving medications for relapse prevention

Alcohol dependence is a chronic disorder that results from a variety of genetic, psychosocial, and environmental factors. Relapse prevention for alcohol dependence has traditionally involved psychosocial and psychotherapeutic interventions. Pharmacotherapy, however, in conjunction with behavioral therapy, is generating interest as another modality to prevent relapse and enhance abstinence. Naltrexone and acamprosate are at the forefront of the currently available pharmacological options. Naltrexone is an opioid receptor antagonist and is thought to reduce the rewarding effect of alcohol. Acamprosate normalizes the dysregulation of N-methyl-D- aspartate (NMDA)-mediated glutamatergic excitation that occurs in alcohol withdrawal and early abstinence. These different mechanisms of action and different target neurotransmitter systems may endow the two drugs with efficacy for different aspects of alcohol use behavior. Since not all patients seem to benefit from naltrexone and acamprosate, there are ongoing efforts to improve the treatment outcomes by examining the advantages of combined pharmacotherapy and exploring the variables that might predict the response of the medications. In addition, novel medications are being investigated to assess their efficacy in preventing relapse and increasing abstinence.

BEHAVIOURAL ASPECTS OF IMPULSIVITY IN ALCOHOLICS WITH AND WITHOUT A CLUSTER-B PERSONALITY DISORDER

AIMS

Studies have shown that alcoholics with a cluster-B personality disorder (cluster-B PD) are characterized by high levels of impulsivity. However, impulsivity has mainly been studied as a broad concept without its different aspects being considered. The present study compared abstinent alcoholic inpatients without any personality disorder (PD) and abstinent alcoholics with cluster-B PD on different aspects of impulsivity, i.e. self-reported impulsivity and neuropsychological indicators such as behavioural control and delay of gratification.

METHODS

Forty alcohol-dependent inpatients without PD and 22 alcohol-dependent inpatients with a cluster-B PD were compared on two self-report impulsivity questionnaires (Barratt impulsiveness scale; sensation-seeking scales) and three behavioural impulsivity tasks [Go/No-Go task; delay discounting task (DDT); Stroop colour word test]. Tests were administered after stable abstinence of at least 3 weeks.

RESULTS

Self-report measures of impulsivity were higher in cluster-B alcoholics than in alcoholics without PD. Behavioural tasks revealed a more differentiated pattern of impairments. On the Go/No-Go task, cluster-B alcoholics were impaired in inhibitory control but not in reaction time compared with alcoholics without PD. In contrast, no significant differences on the DDT and the Stroop were observed.

CONCLUSION

Alcohol-dependent patients with and without a cluster-B PD differ in terms of behavioural inhibition but not in terms of activation or the ability to delay gratification. This finding may partly account for their impulsive and (self-) destructive behaviours. Treatment planning should pay specific attention to these impairments in behavioural control.

DEVELOPMENT AND VALIDATION OF THE AMSTERDAM MOTIVES FOR DRINKING SCALE (AMDS): AN ATTEMPT TO DISTINGUISH RELIEF AND REWARD DRINKERS

Determination of alcoholic subtypes is a promising strategy for patient treatment matching with anti-craving interventions. The aim of this study is to develop and validate a questionnaire on drinking motives that can distinguish relief and reward drinkers.

METHODS

A 103-item self-report questionnaire was developed: the Amsterdam Motives for Drinking Scale (AMDS). The AMDS was tested in two samples of alcoholics (Sample A: n = 251; Sample B: n = 197). The psychometric properties were examined in Sample A and cross-validated in B.

RESULTS

The AMDS consists of a relief scale and a reward scale, both containing distinct subscales. All (sub)scales had good internal consistency. However, the relief and reward scales were highly correlated (Sample A: r = 0.84, P < 0.01; Sample B: r = 0.76, P < 0.01), and convergent and divergent validity was only partly confirmed. The lowest correlations were found between the relief subscale 'stress and vulnerability' and the reward subscale 'stimulation seeking' (Sample A: r = 0.33, P < 0.01; Sample B: r = 0.13, P > 0.01).

CONCLUSIONS

The AMDS reliably measures two types of motives. However, the relief and reward scales are highly correlated. Lower correlations were found only at the subscale level. It is concluded that most treatment-seeking alcoholics have both relief and reward motives. More research is needed on the relationship between motives for drinking and other phenotypic, endophenotypic and genetic indicators of relief and reward drinking, and appropriate cut-off points. Only than we can draw firm conclusions regarding the potential of drinking motives for patient treatment matching.