Psychometric evaluation of a 33-item subset of MOODS-SR for distinguishing bipolar disorder

Introduction The MOODS-SR is a self-report instrument consisting of 161 dichotomous items. It is designed to assess lifetime presence of mood spectrum psychopathology. Recently, it has been proposed that a subset of 33 items can be used to distinguishing bipolar disorder. Aim To evaluate psychometric properties of a 33-item subset and to propose a clinically relevant cut-off for screening for bipolar disorder. Methods Patients with mood disorders were recruited from outpatient services at Sahlgrenska University Hospital. Patients and a convenience sample of healthy controls were offered to fill in the MOODS-SR. A post-hoc analysis was conducted for the 33-items subset of the MOODS-SR. Results The subset showed high internal consistency (Cronbach α = 0.95). The mean scores of patients with bipolar disorder (22.7 ± 6.4) were significantly higher than those of the unipolar (11.3 ± 4.9) and control group (7.0 ± 7.0, P r  = 0.50, P r  = –0.22, P  = 0.223). Conclusion The 33-item subset of MOODS-SR showed promising psychometric properties, including good known-group validity. It discriminated bipolar patients from unipolar patients and healthy subjects. The clinical usefulness of these finding needs further investigation.