The DSM-5 definition of mixed features "specifier" of manic, hypomanic and major depressive episodes captures sub-syndromal non-overlapping symptoms of the opposite pole, experienced in bipolar (I, II, and not otherwise specified) and major depressive disorders. This combinatory model seems to be more appropriate for less severe forms of mixed state, in which mood symptoms are prominent and clearly identifiable. Sub-syndromal depressive symptoms have been frequently reported to co-occur during mania. Similarly, manic or hypomanic symptoms during depression resulted common, dimensionally distributed, and recurrent. The presence of mixed features has been associated with a worse clinical course and high rates of comorbidities including anxiety, personality, alcohol and substance use disorders and head trauma or other neurological problems. Finally, mixed states represent a major therapeutic challenge, especially when you consider that these forms tend to have a less favorable response to drug treatments and require a more complex approach than non-mixed forms.