A minority (9–20%) of subjects facing bereavement may develop symptoms of unresolved grief associated with significant distress and impairment that have been recently identified as a distinct post-loss syndrome named complicated grief. The Inventory of Complicated Grief is a self-report instrument to assess complicated grief. Aim of this study was to: 1) validate the Italian version of the Inventory of Complicated Grief; 2) provide additional evidence of complicated grief diagnosis through analysis of complicated grief symptoms in a clinical data set consisting of bereaved individuals with complicated grief, Post-Traumatic Stress Disorder, bipolar disorder and healthy controls.

229 bereaved subjects were consecutively enrolled: 64 with complicated grief; 72 with post-traumatic stress disorder; 35 with bipolar disorder; 58 healthy controls. Assessments included: the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I/P) and the Italian version of the Inventory of Complicated Grief.

The mean total ICG score was significantly different among the study groups [F(3.228)=94.19, p<.001]. Post-hoc Games-Howell comparisons indicated significantly lower scores in HCS than in the other three groups, and significantly higher scores in CG patients with respect to the other three groups. The scale resulted to have a high level of internal consistency: Cronbach's alpha value computed on the whole sample was 0.947. An exploratory factor analysis (PCA) revealed two components, both with high level of internal consistency (Chronbach's alpha 0.945 and 0.821, respectively). The two components emerged seem to cluster symptoms of separation distress, anger and bitterness, shock and disbelief, behavior change on one side; while hallucinatory symptoms on the other, besides specific symptoms of estrangement from others and one symptom of separation distress.

This study provides evidence of the validation of the Italian version of the ICG, tested in a large and well-characterized clinical help-seeking population. It also supports the proposition that complicated grief is an independent diagnosis.