by summing the number of drinks required to produce an effect and dividing by the numbers of effects endorsed. The SRE has been shown to have good internal consistency and test–retest reliability, provide good validity for identifying people who had low response to alcohol in a laboratory challenge test, and has been associated with AD diagnosis in several populations. A withdrawal severity factor score (WDSFS) was based on ten symptoms in the SSAGA interview (such as hands trembling, feeling anxious following cessation or reduction of drinking). To account for the possible non-equal contribution of each symptom to withdrawal severity, a factor analysis was conducted (for details see Kuo et al., 2006). A factor score of withdrawal severity for each individual was derived based on the item loadings on one major factor, which accounted for 70% of the variance in these symptoms based on the entire IASPSAD sample.
