Affective psychosis is an endogenous mental disease that is characterised by regularly and spontaneously beginning affective phases (depression, mania, mixed states), their complete reversibility after state normalisation, intermission, and recovery of all mental functions.
The definition of affective psychosis meets all the criteria for endogenous diseases previously attributed to MDP (cyclophrenia, circular psychosis, phasic monoor bipolar psychosis).
Affective psychosis is manifested exclusively by affective phases with different degrees of depth and duration. Following ICD-10, the diagnostic criteria for affective phases include their duration of at least one or two weeks with total impairment of the usual working capacity and social activity of the patient; therefore, one should take a physician and begin treatment. Practice shows that ultrashort (with alternation of subdepression and hypomania every other day), as well as extremely long (for several years) phases, can be found. The time interval of one phase and the intermission changing it is referred to be a cycle of affective psychosis.
Hippocrates (the 5th century B.C.) described mania and melancholia as independent diseases although he found cases when melancholic psychoses developed in the same patient. One of the first definitions of melancholia was given by Aretaeus of Cappadocia (the 1st century B.C.), who described it as "depressed state of one's soul for concentrating on the same thought". A sad idea in itself manifests without any special reason, but sometimes they note some emotional excitement preceding the onset of melancholia.
In 1854, J. Falret and J. Baillarger simultaneously described circular psychosis and insanity in a double form, understanding under this phased psychosis, which does not lead to imbecility.