By competitive radioligand binding assay, BP-554 has a Ki = 4.7 nM for binding at the 5-HT1A receptor, with substantial selectivity in vitro (several orders of magnitude) versus a variety of other receptors, including 5-HT1 receptors and 5-HT2 receptors. Serotoninergic transmission selectively mediated through the 5-HT1A receptor has previously shown to be tightly linked to aggression; selective antagonism of 5-HT1A has been shown to reduce aggression. Thus, BP-554 is a potent stimulant of hyperactivity and aggression in humans.