Thought overactivation as a marker of bipolar disorder

Introduction Recent studies have underlined the importance of considering the form of thoughts, beyond their content, in order to achieve a better phenomenological comprehension of mental states in mood disorders. The subjective experience of thought overactivation is an important feature of mood disorders that could help in identifying, among patients with a depressive episode, those who belong to the bipolar spectrum. Objectives Patients with a diagnosis of bipolar disorder (BD) were compared with matched healthy controls (HC) on a scale that evaluates thought overactivation. Aims Validate the Italian version of a scale for thought overactivation (i.e. STOQ) in a sample of bipolar patients. Methods Thirty euthymic BD and 30 HC completed the Subjective Thought Overactivation Questionnaire (STOQ), the Ruminative Responses Scale (RRS), the Beck Depression Inventory-II (BDI-II) and global functioning (VGF). Results The 9-items version of the STOQ has been back translated and its internal consistency in this sample was satisfactory (alpha = .91). Both the brooding subscore of RRS (b-RRS) (r = .706; P < .001) and STOQ (r = .664; P < .001) correlate significantly with depressive symptoms whereas only the first correlate with VGF (r = –.801; P < .001). The two groups did not differed in the b-RRS (HC = 8.41 vs BD = 9.72; P = .21), whereas BD where significantly higher in the STOQ total score (HC = 6.62 vs. BD = 14.9; P = .007). Conclusion Our results, although limited by the small sample size, confirm the validity of the STOQ and suggest that this scale could grasp a feature characteristic of BD, independently from their tendency to ruminate. The latter seems to impact more on global functioning.