Mixed States

"We observe also clinical 'mixed forms'in which the phenomena of Mania and melancholia are combined with each other, so that states arise, which indeed are composed of the same morbid symptoms as these, but cannot without coercion be classified either with the one or with the other. Our customary grouping into manic and melancholic attacks does not fit the facts, if it is to reproduce nature."
Kraepelin, 1921

The co-occurrence of manic and depressive symptoms in MDI are referred to as Mixed State.
The presence of different admixtures of manic and depressive symptoms led Kraepelin to distinguish six types of mixed states.

In 1953, J.D. Campbell wrote: "Manic-depressive (psychosis) is a dynamic, constantly changing process which, at times, may manifest symptoms of both phases simultaneously. It is in the mixed forms that the observer graphically realizes the homogeneity of the entire process." (p. 146)

Mixed states occur during the transition from one phase to another, or as stable clinical manifestations of overlapping symptoms.

A recent review of the literature on Mixed States examined diagnostic criteria used reported rates of 30-40% among patients with MDI, and described clinical features and neurobiological characteristics. (McElroy)

Like all MDI manifestations, Mixed States are distributed on a continuum, from severe manic symptoms with mild depressive features (Mixed Mania and Dysphoric Mania) to severe depressive symptoms with hypomanic features (Agitated Depression and Mixed Depressive Syndromes, Kukopulos).

The relationship between these syndromes, illness subtype and premorbid temperament has been the subject of intensive study by Akiskal and colleagues.