RESUMEN
Youth self-harm is associated with poor health outcomes and attempted and completed suicide. Associations exist between self-harm and expressed emotion (EE), attachment insecurity, and reflective functioning (RF), but these associations are poorly understood. This study evaluates a mediation model in which perceived caregiver EE (pEE) exerts an indirect effect on youth self-harm through attachment insecurity and RF uncertainty. 461 participants aged 16-24 years completed an online survey. Statistical analyses revealed significant direct effects of pEE on attachment insecurity, and of RF uncertainty on self-harm; however, some direct effects were specific to pEE from female caregivers, and attachment insecurity in youth relationships with female caregivers. A significant direct effect of pEE on self-harm was found for pEE from male caregivers only. Significant indirect effects of pEE on self-harm through attachment anxiety and RF uncertainty were found only in relation to female caregivers. The findings encourage family-, attachment-, and mentalization-based approaches to preventing and treating youth self-harm, with a recommendation that caregivers are given adequate support, education, and skills-based training following youth disclosures of self-harm. Supplementary Information: The online version contains supplementary material available at 10.1007/s12144-022-03614-w.