The Effects of Intranasal Oxytocin on Social Cognitive Functioning in Adolescents with Borderline Personality Disorder Compared to a Sample of Non-Clinical Adolescents

Borderline Personality Disorder (BPD) is a severe psychiatric disorder where interpersonal dysfunction is central as a result of impairments in social cognitive abilities, specifically in mentalizing. A neuropeptide model of BPD has been proposed, suggesting that the oxytocin system is dysregulated, which contributes to the onset of interpersonal symptoms of the disorder (Stanley & Siever, 2010). To further understand the social-cognitive mechanisms involved BPD in adolescents, the current study investigated the effects of intranasal oxytocin on in-vivo mentalization in a sample of BPD patients in comparison to a group of non-clinical adolescents (ages 12-17) using a double-blind, randomized, and placebo-controlled experimental design. A secondary aim was to investigate whether trait-based mentalization moderated the effects of oxytocin and in-vivo mentalizing in adolescents, regardless of BPD status. In an age- and gender- matched sample of 40 adolescents (BPD/non-clinical = 20/20), no significant effects were found for condition (oxytocin and placebo) or group (BPD and non-clinical) on overall in-vivo mentalizing or hypermentalizing. However, trait-based mentalizing was found to be a significant moderator for the relation between oxytocin and in-vivo mentalizing. Adolescents with high trait-based mentalizing displayed higher overall in-vivo mentalization after delivery of oxytocin in comparison to placebo. In contrast, adolescents with low trait-based mentalizing displayed lower overall in-vivo mentalization after oxytocin delivery compared to placebo. Trait-based mentalizing was also found to be a significant moderator on oxytocin and hypermentalizing. Adolescents with high trait-based mentalizing scored lower on hypermentalizing after receiving oxytocin in comparison to placebo, while adolescents with low trait-based mentalizing scored higher on hypermentalizing after oxytocin delivery in comparison to placebo. These findings are an important extension of the oxytocin research in BPD, which have only been investigated in adults thus far with several studies demonstrating the differential effects of intranasal oxytocin on social cognition. Indeed, in the current study, differential effects of oxytocin on social cognition were found for adolescents, with trait-based mentalizing moderating the relation between oxytocin and in-vivo mentalization. Adolescents with high trait-based mentalizing scored higher on in-vivo mentalization after receiving oxytocin in comparison to adolescents with low trait-based mentalizing, who scored lower on in-vivo mentalization after oxytocin delivery. Therefore, important moderators including individual characteristics such as trait-based mentalizing, age, gender, and other factors need to be considered in future evaluations of intranasal oxytocin as a potential intervention for adolescents diagnosed with BPD.