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 Teens are more likely than adults to report that their stress level has a slight or no impact on their body or physical health (54 percent of teens vs. 39 percent of adults) or their mental health (52 percent of teens vs. 43 percent of adults). Although teens do not appear to recognize the potential impact of stress on their physical and mental health, they often struggle to cope. 2  Only 50 percent report feeling confident about their ability to handle their personal problems, and 46 percent say they feel that they are on top of things fairly or very often.