Parent-youth and peer relationship inventories based on attachment theory measure communication, trust, and alienation, yet sibling relationships have been overlooked. We developed the Sibling Attachment Inventory and evaluated its psychometric properties in a sample of 172 youth ages 10-14 years. We adapted the 25-item Sibling Attachment Inventory from the Inventory of Parent and Peer Attachment-Revised peer measure. Items loaded onto three factors, identified as communication, trust, and alienation, α = 0.93, 0.90, and 0.76, respectively. Sibling trust and alienation correlated with depression (r = -0.33, r = 0.48) and self-worth (r = 0.23; r = -0.32); sibling trust and alienation correlated with depression after controlling for parent trust and parent alienation (r = -0.23, r = 0.22). Preliminary analyses showed good internal consistency, construct validity, and incremental predictive validity. Following replication of these properties, this measure can facilitate large cohort assessments of sibling attachment.
