In the present study, we are interested in several alcohol-related phenotypes, which are hypothesized to be associated with GAD genes, including age-at-onset of AD, subjective response to ethanol, and withdrawal symptoms. Age-at-onset (ONSET) was defined as the age at which the first criteria for DSM-IV AD was met. Subjective response to ethanol was measured using the Self-Rating of the Effects of Alcohol, SRE (Schuckit et al., 1997) to form two scores, initial sensitivity (ISENS) and tolerance/maximum drinking (TOLMX). The SRE asks how many drinks were required for an individual to experience effects (e.g. feel dizzy, begin stumbling, or pass out) from alcohol consumption at different stages of alcohol use. ISENS is based on “the first 5 times you ever drank” and items contributing to TOLMX concern the “period when you drank the most”. The score of each measure was computed 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
