The Approach and Avoidance Task (AAT) in Alcoholic Inpatients

The approach and avoidance task (AAT) has evolved as a promising treatment add-on in the realm of psychology. Certain psychiatric diseases, such as behavioural addictions, social anxiety disorder, and arachnophobia, are characterized by a dysfunctional tendency to either approach or avoid disease-specific objects. This tendency can be measured by means of the approach and avoidance task. In this so-called diagnostic AAT participants are instructed to react upon the format or the frame colour of a picture. For instance, pictures have to be pushed away if they are presented in landscape format and pulled towards oneself if they are presented in portrait format (or vice versa). Hence, the format (or the frame colour) becomes the task-relevant dimension, whereas the content of the picture becomes the task-irrelevant dimension. However, what generally becomes obvious in the psychiatric diseases mentioned above is that the task-irrelevant dimension (picture content) exerts an influence on reaction times. For instance, alcoholic patients are generally faster to respond if alcoholic pictures are presented in a format requiring them to pull towards themselves and slower to respond if alcoholic pictures are shown in the format requiring them to push away a joystick. This behavioural tendency has been termed an approach bias for alcohol.

In order to counteract these dysfunctional approach or avoidance tendencies, an AAT-training has been developed. In this training participants/patients learn to either avoid or approach disease-specific objects. Alcohol-dependent patients, for instance, learn to avoid alcohol-related pictures by pushing or swiping the image away. It has been shown that these trainings can enhance treatment outcome (e.g. lower relapse rates) among alcohol-addicted patients (Wiers, Eberl, Rinck, Becker, \& Lindenmeyer, 2011). The aim of the current study is to test whether the avoidance gesture is as important as suggested by the AAT's name or whether inhibiting the urge to approach alcoholic content might be enough to bring about the effect.

The approach and avoidance task (AAT) has turned out as both a promising diagnostic tool as well as treatment add-on in psychological science. The AAT constitutes one form of cognitive bias modification (CBM), which has been shown to be particularly effective in the field of behavioral addictions, such as alcohol addiction (Eberl et al., 2013; Wiers et al., 2011). The general logic underlying the AAT is to carry out actions that are either compatible or incompatible with an individual's action tendencies. For instance, alcohol addicted patients tend to approach alcohol related stimuli faster than control pictures (i.e. soft drink stimuli), when they are instructed to react upon the format of a picture and not to its' content. This tendency of comparatively faster approaching and slower avoiding alcohol-related stimuli than soft drink content has been termed an approach bias for alcohol. The AAT as a therapeutic tool tries to counteract or at least to attenuate approach or avoidance biases by instructing patients to carry out approach and avoidance gestures that are in conflict with an individual's acquired action tendencies.

Whereas the general effectiveness of the AAT as a clinical intervention has been demonstrated several times, little is known about possible mechanisms that might subserve these effects. Therefore, the current study is dedicated to shed some light on one such potential mechanism, i.e. the role of the avoidance gesture within the alcohol-AAT.

As already suggested by the name of the AAT, the avoidance gesture seems to be a key ingredient in bringing about therapeutic effects. However, recent empirical evidence has brought about some interesting findings, giving rise to an alternative explanation.

A study by Kühn et al. (2017), contrary to common-held beliefs, indicated that inhibition capacity can be trained. Inhibition, in turn, consistently has been linked to psychopathology and all kinds of behavioural addictions (Smith, Mattick, Jamadar, \& Iredale, 2014). The game by Kühn et al. (2017) used to train inhibition resembled the AAT in several ways, e.g. certain stimuli appearing on a treadmill had to be collected by swiping towards oneself and others had to be ignored and the objects slowly disappeared. The latter element contrasts with the AAT, since the ignored objects don't have to be pushed away. However, it resembles the AAT in the sense that in both cases stimuli slowly fade out of the screen and eventually disappear. These parallel let to the assumption that a new form of the alcohol AAT training might be equally effective in lowering relapse rates among alcoholic patients. More precisely, within the newly conceptualized AAT training patients are instructed to inhibit the urge to respond in response to alcohol-related content and to observe the stimuli fading out of the screen. In contrast, to the classical AAT training this zooming out of alcoholic stimuli is not conditional on an avoidance gesture, i.e. swiping/pushing away the stimulus.

It is hypothesized that compared to a control group, in which alcohol and soft drink stimuli have to be swiped to the left and right, both the classical AAT-and the inhibition group will show lower relapse rates and approach biases after the intervention, i.e. a training period of three weeks. No intergroup differences in terms of relapse rates and alcohol-related approach bias are expected for the classical AAT group and the inhibition group.

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of alcohol dependence (SKID-I)
* Abstinence from alcohol (at least 72 hours) and absence of major withdrawal symptoms
* Being in between 18-76 years of age
* Being able to understand rationales of the study and signing written informed consent
* Currently being inpatient seeking help overcoming alcohol dependence
* Medication allowed: Antiepileptic's (such as Carbamezepin), antidepressants, substances to treat other non-psychiatric diseases

Exclusion Criteria:

* Impaired ability to cooperate
* Presence of another substance dependency than alcohol and nicotine within the last year
* Presence of another axis-I disorder that interferes with the ability to cooperate within the study programme
* Current episode of a major depression
* Presence of axis-II disorders
* Presence of schizoaffective disorders
* Alcohol consumption in between withdrawal and start of the study
* Somatic or neurological disease that precludes the proper execution of the study
* Long-term intake of neuroleptics or hypnotics
* Current intake of benzodiazepines or Clomethiazol (in the period of five half-value times prior to the start of the study)
* Participation in other studies or other treatments than treatment as usual
* Planned long-term therapy after 3-week withdrawal programme
* Being homeless
* Prior electroconvulsive therapy
* Language barriers that preclude proper understanding of study contents