Mixed states: Still a modern psychopathological syndrome?

Objectives The aim of this review is to evaluate whether the DSM-5 concept of mixed features "specifier" provides a definition that reflects the richness and multiplicity of this psychopathological picture pointing out the historical development, clinical conceptualisation and proposed therapeutic approach to mixed states. Methods We review and discuss the recent evidence on the presence of mixed features during mania and depression and summarise findings on the conceptualisation of mixed states. Electronic searches of all English-language papers were performed in the MEDLINE and PUBMED database using and cross-listing key words: mixed state, mixed features, bipolar disorder, major depressive disorder, mania, hypomania, depression. Results The mixed categorical-dimensional concept used in the DSM- 5 broadens the concept of mixed episodes, introducing substantial changes to the diagnosis of mixed states. This definition appears more appropriate for less severe forms of mixed states presenting clear and detectable mood symptoms with evident improvement compared to the DSM-IV, as the possibility of classifying depression "with mixed features". Conclusion The transition from the classical definition of mixed states to the one reported in the DSM-5 has determined a complex modification of the concept of mixed state. The DSM-IV-TR description, based on the co-presence of symptoms of opposite polarity, was extremely reductive and did not capture the sub-syndromal symptoms of the opposite pole experienced in bipolar and major depressive disorders. The DSM-5 definition of mixed features "specifier" represents a valid tool to improve the recognition and proper treatment of bipolar mixed patients, reducing misdiagnosis and mistreatment associated with chronic and repetitive exposure to antidepressants and sedatives, although the mixed categorical-dimensional concept does not adequately reflect some overlapping mood criteria, such as mood lability, irritability and psychomotor agitation.