Research report Towards a reconceptualization of mixed states, based on an emotional-reactivity dimensional model Chantal Henry ⁎ , Katia M'Baïlara, Alain Desage, Sébastien Gard, David Misdrahi, Eduard Vieta Hôpital Charles Perrens, Bâtiment Lescure, 121 rue de la Béchade, 33076 Bordeaux Cedex, France Laboratoire de Psychologie Clinique et Psychopathologie JE 2358, 3 ter place de la Victoire, Université Victor Segalen, Bordeaux 2, Bordeaux, France Bipolar Disorders Program, Hospital Clinic, IDIBAPS, Clinical Institute of Neuroscience, University of Barcelona, Villarroel 170/Rossello 140, 8036 Barcelona, Spain Received 29 October 2006; accepted 30 October 2006 Available online 22 January 2007 Abstract Background: DSM-IV criteria for mixed states may be too restrictive and may actually exclude patients who do not meet the full criteria for a manic and depressive state. Using this DSM-IV definition, many patients who are considered depressed may have mixed features, which can explain why some bipolar depressive states can worsen with antidepressants and can be improved by mood stabilizers or atypical antipsychotics. A dimensional approach not exclusively focused on the tonality of affect would help to define a broader entity of mixed states. The aim of this study was to apply a dimensional model to bipolar episodes and to assess the overlap between the groups defined using this model and using categorical diagnosis. Method: We assessed 139 DSM-IVacutely ill bipolar I patients with MAThyS (Multidimensional Assessment of Thymic States by Henry et al. in press), a scale that assesses five quantitative dimensions exploring excitatory and inhibition processes, and that is not focused on tonality of mood but on emotional reactivity. We studied the relationship between clusters defined by statistical analyses and DSM-IV bipolar mood states. Results: This study showed the existence of three clusters. Cluster 1 was characterized by an inhibition in all dimensions and corresponded to the depressive cluster (more than 90% of patients met the criteria for DSM-IV Major Depressive Episode (MDE)). Cluster 2 showed a general excitation and was mainly DSM-IV manic or hypomanic patients (90%). Cluster 3 (Mixed) was more complex and the diagnosis included MDE (56%) in most of the cases associated with manic or hypomanic symptoms, mixed states (18%) defined by DSM-IV criteria, and manic or hypomanic states (25%). Emotional reactivity was relevant to distinguish Cluster 1 (Depressive), exhibiting emotional hypo-reactivity, from Cluster 2 (Manic) and 3 (Mixed), characterized by emotional hyper- reactivity. Sadness was reported equally in all three clusters. Conclusion: A dimensional approach using the concept of emotional reactivity seems appropriate to define a broad mixed state entity in patients who would be diagnosed with MDE according to DSM-IV. Further studies are needed to test the relevance of this model in therapeutic strategies. © 2006 Elsevier B.V. All rights reserved. Keywords: Bipolar disorders; Mixed states; Major depressive episode; Emotional reactivity; Treatment Journal of Affective Disorders 101 (2007) 35 – 41 www.elsevier.com/locate/jad ⁎ Corresponding author. Tel.: +33 5 56 56 34 50; fax: +33 5 56 56 17 14. E-mail address: chenry@perrens.aquisante.fr (C. Henry). 0165-0327/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jad.2006.10.027