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).
Child and Adolescent Bipolar Disorder: An Update from the National Institute of Mental Health. Research findings, clinical experience, and family accounts provide substantial evidence that bipolar disorder, also called manic-depressive illness, can occur in children and adolescents. Bipolar disorder is difficult to recognize and diagnose in youth, however, because it does not fit precisely the symptom criteria established for adults, and because its symptoms can resemble or co-occur with those of other common childhood-onset mental disorders.