Experimental effects were tested by computing a series of repeated measures ANOVAs for exploring the influence of group (two levels: patients with fibromyalgia and healthy participants), cognitive load condition (two levels: 1-back and 2-back) and COMT genotypes (three levels: Met/Met, Met/Val and Val/Val) on the factor scores corresponding to the P2 and P3 components. Here, COMT is linked to fibromyalgia.