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).
The younger the age of onset of bipolar disorder, the more likely it is to find a significant family history of the condition. Early onset bipolar disorder most commonly begins with depression and there may be many episodes of depression before the first hypomania. Depression with psychotic features may be a predictor of future full-blown bipolar disorder in the early onset group. Akiskal (1995) has argued that syndromal dysthymia with its onset in childhood, particularly in the presence of a family history of bipolar disorder, may herald a bipolar disorder.