The effects for heavy drinking days were similar to those for DDs, so they are not presented graphically. There was a significant four-way interaction of cluster type, medication group, genotype, and week (t = 2.89, p = 0.005) on heavy drinking days. Conditioned on genotype, the three-way interaction of cluster type, medication group, and week was significant among L′ homozygotes (t = 2.77, p = 0.014), but not among S′ carriers (t = 1.11, p = 0.27). Among L′ homozygotes, Type B alcoholics reported more heavy drinking days when treated with sertraline than placebo, while Type A alcoholics showed the opposite effect.
