The Inventory of Complicated Grief (ICG) is the most widely used instrument to measure complicated grief (CG), but its psychometric properties have hardly been examined in relatives of those who died by violent means. The objective of this study was to obtain evidence of validity of the ICG in a relatives of those who died due to terrorist attacks in Spain. The factorial structure, internal consistency, and relationship with depression, anxiety, and post-traumatic stress were analyzed in a Spanish sample of 211 relatives of people who died in terrorist attacks. The ICG presented a one-factor structure that supports the validity of its total score. This score showed excellent internal consistency indices (alpha = .927; omega = .932) and adequate correlation indices with depression, anxiety, and post-traumatic stress (r = .71, .63 and .76, respectively). The ICG provides reliable and valid measures of CG in adults who have lost a family member due to violent death.
Keywords: complicated grief; factorial structure; inventory of complicated grief; reliability; validity.