Polycythemia (also known as polycythaemia or polyglobulia) is a disease state in which the proportion of blood volume that is occupied by red blood cells increases. Blood volume proportions can be measured as hematocrit.It can be due to an increase in the number of red blood cells (absolute polycythemia) or to a decrease in the volume of plasma (relative polycythemia).lood volume proportions can be measured as hematocrit. It can be due to an increase in the number of red blood cells (absolute polycythemia) or to a decrease in the volume of plasma (relative polycythemia).
1 Some 20% of adolescents with major depression develop bipolar disorder within five years of the onset of depression. ( 2 Birmaher, B., Childhood and Adolescent Depression: A Review of the Past 10 Years.. 3  Part I, 1995).
1 Children of a parent with bipolar disorder have a 50% chance of having a major psychiatric illness. 2  Children remain at an increased risk even if they are raised in the home of parents without the illness.