Development and validation of the Amsterdam Motives for Drinking Scale (AMDS): an attempt to distinguish relief and reward drinkers.

UNLABELLED 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.