The integral inventory for depression, a new, self-rated clinimetric instrument for the emotional and painful dimensions in major depressive disorder

Objective. To assess the reliability and validity of the Integral Inventory for Depression (IID) scale using post hoc analyses of data from a multi-country study (ClinicalTrials.gov:NCT00561509) of patients with major depressive disorder (MDD). Methods. Patients (N = 1629) completed the IID (comprising two separate dimensions for emotional and physically painful symptoms; maximum score of 65) and a reference scale (16-item Quick Inventory of Depressive Symptomatology Self-Report) at baseline and at follow-up (8 and 24 weeks). Physicians rated MDD symptoms using the Clinical Global Impressions of Severity scale at each visit. Inter-item correlation, internal consistency, external validity, factor structure, and exploratory analysis of an optimal severity cut-off point were assessed. Results. The IID displayed two distinct dimensions (i.e. painful and emotional) with little item redundancy and good internal consistency (Cronbach's alpha > 0.83 at each visit). The IID displayed good external validity (Pearson's correlations coefficients >0.60 at each visit) and statistically significant agreement (McNemar's test; P < 0.001 at follow-up) with the reference scale. Results suggest that a cut-off score of <= 24 had adequate precision (>80%) to identify patients with and without moderate MDD. Conclusions. Results suggest that the IID may be a reliable and valid tool for assessing emotional and painful symptoms of MDD.