Disorganized Attachment and Identity Dissociation: FKBP5 CATT as a Molecular Moderator

• Disorganized attachment predicts identity dissociation in trauma-exposed adults. • The FKBP5 CATT haplotype moderates the link between attachment and dissociation. • CATT carriers show a 16.5% increase in identity dissociation per unit of disorganized attachment. • FKBP5 CATT does not increase the risk of forming a disorganized attachment. • Genetics amplify the translation of attachment issues into identity fragmentation. Childhood maltreatment and FKBP5 CATT haplotypes increase identity dissociation risk. While maltreatment often fosters disorganized attachment, the specific role of the FKBP 5 CATT haplotype within this developmental pathway remains unknown. In 310 trauma-exposed adults, we assessed childhood maltreatment, disorganized attachment, and identity dissociation. FKBP 5 CATT haplotype status was dichotomized (present/absent). Regression models were estimated to examine the pathway Childhood Maltreatment → Disorganized Attachment → Identity Dissociation, comparing two competing hypotheses: 1) The Formation Hypothesis (Maltreatment × CATT → Disorganization), and 2) The Translation Hypothesis (Disorganization × CATT → Identity Dissociation). Model fit was compared using BIC, and simple slopes were examined. Disorganized attachment predicted identity dissociation (β = 0.143, z = 3.83, p < .001), and childhood maltreatment predicted disorganization (β = 0.007, z = 4.46, p < .001). The Formation hypothesis was not supported, as the Maltreatment × CATT interaction did not predict disorganization (β = -0.004, z = -1.18, p = .24). However, the Translation hypothesis was supported by three pieces of evidence: a significant Disorganization × CATT interaction predicting identity dissociation (β = 0.133, z = 2.22, p = .027), model fit (∆BIC = 265.3), and simple slopes showing a strong effect of disorganization on identity dissociation for CATT carriers (β = 0.15, p < .001; +16.5% per unit) but not for non-carriers (β = 0.02, p = .65). The FKBP 5 CATT haplotype does not promote disorganized attachment but amplifies the translation of disorganized attachment into identity dissociation. This result highlights a genetically influenced failure of identity development following disorganized attachment.