THE EFFECTS OF ALCOHOL PRIMING ON DISINHIBITION:

1. THE EFFECTS OF ALCOHOL PRIMING ON DISINHIBITION: using an Alcohol Hayling-style Task and Alcohol Stroop Task Navin Kumar & Abigail Rose King’s College London, Institute of Psychiatry INTRODUCTION Alcohol is consumed by people all over the world, in social situations to enjoy themselves and, in some cases, to gain health benefits when taken in moderate quantities. However, alcohol misuse is on the rise, with 24% of the UK adult population classed as hazardous and harmful drinkers (Adults psychiatric morbidity survey, 2007. The NHS Information Centre). Significant health, social and economic problems associated with drinking continue to rise (NHS Information Centre, 2009). It is important to understand the factors which determine hazardous drinking behaviour to produce interventions/treatments and to create health policies which are evidence-based. There are a number of management strategies for alcohol misuse which vary in their approaches. This is due to the multiple viewpoints and complexity in its aetiology. Ball and Murray (1994) found supporting evidence between genes and alcoholism, especially in terms of a person’s response to alcohol consumption. Other studies have addressed psychological predisposition, including roles of learning theories, expectancies and self-efficacy. Another proposed idea suggests disinhibition may be an important factor in alcohol misuse. Disinhibition is where a person has reduced self-restraint to their impulsive response to a situation. Impulsive individuals, therefore, are prone to react to their feelings at the moment in time, with a lack of reflectiveness and planning, rapid decision-making and actions, and carelessness, and with little normal control of choosing to inhibit inappropriate behaviour (Magid et al., 2007). Previous research suggests initial consumption of alcohol triggers disinhibition. This effect may be involved in the drinking phenomena called alcohol priming (Rose and Duka, 2007; Rose and Grunsell 2008). Alcohol priming occurs when an initial dose of alcohol is consumed and may draw an individual to alcohol, increase consumption and prolong drinking (Rose and Duka 2007, de Wit 2000). This study extends previous research by using a priming paradigm to establish the acute effects of alcohol on disinhibition and role of trait disinhibition on behaviour. In previous studies the Stroop task is one of the usual methods to measure disinhibition. Despite this being a well-validated technique, it has some limitations. The stimuli are determined in isolation from the participant who remains ‘passive’. For example, the Stroop includes predetermined colour and alcohol words (Rose & Duka, 2007, 2008). In response, Rose et al. (2010) developed and piloted a tool for measuring disinhibition based on the Hayling task, a sentence completion test of inhibition requiring the active participation of individuals. The Hayling task is split in two sections: i) participants end sentences with an expected word which makes contextual sense (initiation); ii) participants must inhibit a semantically correct word and complete sentences with an unrelated word (inhibition). Both these methods to measure disinhibition were used in this study. METHOD Twenty one participants took part (11 males). Mean age was 24.0 years (SEM+/- 1.9, range 18.1 to 58.6). Participants were recruited through email within King’s College London and the Institute of Psychiatry’s Mind Search database. Participants completed two sessions, in one session participants were given an alcohol prime (0.6 g/kg) and in the other, participants were given a placebo. A number of questionnaires were used in this study to obtain the information required. The Independent variables used during this study were: alcohol cognitions (self-report: Alcohol Expectancy Questionnaire, Temptation & Restraint Inventory), trait impulsivity (Barratt’s Impulsivity Scale) and typical drinking behaviour (Alcohol Use Questionnaire, Time Line Follow Back). The Dependent variables were self-reported mood visual analogue scales (VAS) and alcohol urge (alcohol urge questionnaire), and disinhibition task performance (number of errors made and response latency). During each session, the participants were required to undertake both the alcohol Hayling-style Task and alcohol Stroop Task, 30 minutes after finishing their last drink (when alcohol priming has peaked in previous research [Rose & Duka, 2006]). Mixed measure ANOVA & Bonferroni corrected correlation analysis were conducted using SPSS. RESULTS • Results from the self-reports pre and post consumption (alcohol or placebo), indicated an interaction between drink and time [F(1, 20)=4.29, p=0.05), although alcohol urge remained stable over time in the placebo condition, urge increased after alcohol consumption (see Graph 2). • The Mood VAS questionnaire found participants became increasingly lightheaded, contented, and sedated, after the consumption of alcohol. • The Biphasic Alcohol Effects Scale found during both the sessions, alcohol or placebo, participants became more relaxed after consuming the drink provided [F(1,20)=10.32, p=0.004]. • Paired t-tests were used to compare Stroop across drink type. Error rates differed significantly across conditions on the alcohol [t(20)=2.42, p = 0.03); positive [t(20)=2.26, p = 0.04]; negative [t(20)=2.45, p = 0.02]. There was also a strong trend for a difference across condition with the Original Stroop [t(20)=2.0, p=0.06]. In all cases, participants made more errors after alcohol compared with placebo (see Graph 1). • The Hayling task found the alcohol caused participants to give more alcohol related answers during the initiation phase, and took longer to give these during the inhibition phase, [F(1,19)=4.2, p=0.05]. • By running a between subject ANOVA analysis on the Barratt’s Impulsivity Scale, it was found there were interactions between Stroop and impulsivity [F(5,95)=2.40, p=0.04], and drink, Stroop and impulsivity [F(5,95)=5.30, p<0.01). The participants who were naturally more impulsive became more impulsive after consuming alcohol, but not after the placebo drinks. Graph 1 Graph 2 CONCLUSIONS These results confirm previous findings that a moderate dose of alcohol (0.6, g/kg) can prime non-dependent drinkers (Rose & Duka, 2006). This increased desire to acquire more drink after an initial drink, is a plausible reason for individuals to binge drink. Positive experiences were perceived by the subjects after consuming alcohol, such as lightheadedness, increased contention and the sensation of being relaxed. These positive reinforcing effects may strengthen positive alcohol expectancies and, therefore, encourage increased drinking patterns in the future. Despite the stimulant effects of acute alcohol consumption not being apparent in the individuals from this study, sedative effects were. However, the positive affect recorded (e.g. relaxed, contented) may be interpreted as positive sedative effects and could encourage future alcohol consumption via negative reinforcement (e.g. stress relief). Disinhibition was apparent after the individuals were primed with alcohol, as the participants had increased errors on the Stroop task during the alcohol condition. Furthermore, attentional bias was also evident after the consumption of alcohol, indicated by the initiation phase of the Hayling task, as the participants continued to present more alcohol related answers after consuming alcohol. These two factors, in combination with increased impulsivity after being primed, help to explain why people are drawn into binge drinking after an initial drink. Disinhibition is a multifaceted construct and many different tasks have been developed which assess specific components involved in control. From these results, it can be understood that an alcohol-related attentional bias may lead to disinhibition. When individuals are focusing on alcohol and nothing else, they may not take in all the environmental information needed to behave appropriately in a given situation. This may make their behaviour appear disinhibited by others but the underlying mechanisms are related to attention rather than control per se. References Ball D and Murray R (1994). 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