Oxytocin modulation of self-other distinction is replicable and influenced by oxytocin receptor (OXTR) genotype

Intranasal oxytocin (OXT) has been associated with effects on diverse social-emotional domains in humans, however progress in the field is currently hampered by poor replicability. Limited statistical power and individual differences in biological factors, such as oxytocin receptor (OXTR) genetics, may have contributed to these variable findings. To this end, we present a pharmaco-genetic study aiming at (1) replicating previous findings suggesting that intranasal oxytocin (24 IU) blurs self-other distinction in a large sample of n = 170 male subjects, (2) determining whether variations in common receptor polymorphisms (rs237887, rs2268491, rs2254298, rs53576, rs2268498) influence sensitivity to oxytocins behavioral effects. Employing a validated oxytocin-sensitive trait judgment paradigm, we confirmed that it blurred self-other distinction in terms of decision time and subsequent memory. However, oxytocin only influenced decision time in rs53576 G carriers, whereas effects on memory performance were most pronounced in rs2268498 TT homozygotes. In summary, the current study replicates our previous findings showing that oxytocin blurs self-other distinction and suggests that sensitivity to its effects in this domain are receptor genotype dependent.