A randomized, controlled trial on the added value of online cognitive bias modification avoid-alcohol training (CBM AAT) on web-based cognitive behavioural treatment (TAU) for problem drinkers

The main study parameter is the percentage of participants reporting alcohol

consumption below problem drinking limits (<22 standard units/week for men and

<15 for women).

Health status will be assessed with the Maudsley Addiction Profile, Health

Symptom Scale (MAP-HSS). The MAP-HSS is a ten-item structured interview, which

was adapted from the health scale of the Opiate Treatment Index (Marsden et

al., 1998).



Quality of life will be measured with the EuroQol-5D (EQ-5D) (Lamers et al.,

2005). The EuroQol-5D is a generic quality-of-life (QoL) instrument which

consists of 5 domains: mobility, self-care, usual activities, pain/discomfort

and anxiety/depression. In addition, participants were asked to rate quality of

life in the last week, in comparison with last year, by means of a visual

analogue scale (VAS).



Depression, anxiety and stress will be measured with the 21-item Depression

Anxiety Stress Scale (DASS-21) (Antony et al., 1998).



Approach-bias: Approach-bias is measured with an AAT (Wiers et al., 2009), ),

in the pre-assessment and post-assessment. The assessment AAT will begin with

12 practice pictures in which participants learn to avoid or approach the

picture in response to the tilt of the picture (tilted left or right). The

practice phase will be followed by the pre-assessment, consisting of 160 test

pictures in which pictures of alcoholic drinks and non-alcoholic drinks come

equally often in push- or pullformat (e.g. tilted left and right). To control

for confounding by left-right preferences picture format will be

counterbalanced, with half the participants pulling pictures tilted to the left

and half pulling pictures tilted to the right. An AAT bias index is calculated

as the difference between the median reaction time scores for pushing pictures

of one category (alcohol or soft drinks) and the median reaction time score for

pulling pictures of that category. Median scores are used to minimize the

influence of outliers. Positive scores indicate approach tendencies and

negative scores indicate avoidance tendencies.



Background variables that will be assessed at baseline are gender, age,

education level, employment, alcohol dependence, and treatment motivation. We

will also assess the number of completed sessions and TAU sessions.



Type and severity of alcohol dependence at baseline will be assessed by using

the DSM-IV, by means of the Substance Abuse Module of the Composite

International Diagnostic Interview (Compton et al., 1996).



Baseline Drinking Motives will be measured with the modified Drinking Motives

Questionnaire Revised (mDMQ-R, Cooper, 1994). The mDMQ-R is a 28-item

self-report inventory that assessed the relative frequency of drinking for each

of the four motives in Cooper*s (1994) model. Participants indicate their

relative frequency of alcohol use for each of the listed reasons on a scale

ranging from 1 (almost never/never) to 5 (almost always/always).



The 5-item Obsessive Compulsive Drinking Scale (OCDS) is derived from the

original 14-item OCDS scale. The OCDS reflects obsessionality and compulsivity

related to craving and drinking behavior (Anton et al., 1995).



Drinking Refusal Self-efficacy (Oei et al., 2005) will be assessed with 8 items

covering all 3 subdimensions of self-efficacy: social pressure, emotional

relief, and opportunistic. Drinking refusal self-efficacy is considered an

important cognitive mechanism within the reflective system that predicts

treatment outcome. We hypothesize that when baseline self-efficacy is low, the

additional effect of the CBM Avoid Alcohol training will be stronger.

Additionally, time-varying self-efficacy is expected to mediate the CBM effect

as repeated experiences of successful coping due to stronger avoidance

responses will enhance refusal self-efficacy.



Credibility of the CBM training will be assessed with the Credibility and

Expectancy Questionnaire (CEQ, Devilly & Borkovec, 2000). Directly after the

first session of training, participants complete this questionnaire It contains

six items and differentiates between one*s thoughts and feelings regarding the

CBM training.



Client Satisfaction regarding the CBM training will be assessed with the Client

Satisfaction Questionnaire (CSQ; de Brey, 1983).The questionnaire contains 8

items and answers are given on a 4-point scale.