• The simultaneous existence of manic and depressive symptoms in a manic-depressive patient was first described by Kraepelin.1 This so-called mixed state has come to have much theoretical significance in recent hypotheses about the nature of bipolar affective disorders.
In this investigation a mixed state is shown to be the initial episode in 31% of 84 manic-depressive outpatients. Moreover, the presence of "mixed" features does not correlate with severity of illness or mood circularity, but does correlate with sedative abuse and poor response to psychopharmacologic treatment. These results suggest that the "continuum hypothesis" and its satellite theories represent viable conceptualizations of the nature of manic-depressive illness.
Himmelhoch JM, Mulla D, Neil JF, Detre TP, Kupfer DJ. Incidence and Significance of Mixed Affective States in a Bipolar Population. Arch Gen Psychiatry. 1976;33(9):1062–1066. doi:10.1001/archpsyc.1976.01770090052004