Are manic symptoms that 'dip' into depression the essence of mixed features?

Background: Three symptoms of (hypo)mania that clinically represent mood disorders mixed states have been omitted from the DSM-5 mixed features specifier because 'they fail to discriminate between manic and depressive syndromes'. Therefore, the present study examined the role of distractibility, irritability and psychomotor agitation (DIP) in characterising mixed depressive states.

Methods: Fifty in-patients at a specialist mood disorders unit underwent a detailed longitudinal clinical evaluation (3-6 weeks) and were assessed on a range of standardized measures to characterise their illness according to depression subtype, duration of illness and clinical features-including specifically depressive and manic symptoms and the context in which these occur.