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 Between 10 to 15 percent of teenagers have some symptoms of teen depression at any one time. 2  About 5 percent of teens are suffering from major depression at any one time. 3  As many as 8.3 percent of teens suffer from depression for at least a year at a time, compared to about 5.3 percent of the general population.