Severe thinness is the result of substantial loss of fat and muscle tissue. People may become victims of severe thinness intentionally, but severe thinness may also affect starving people.
Severe thinness develops due to disproportion between energy intake and energy expenditure. Severe thinness is frequently accompanied by a constant appetite loss. Severe thinness may appear as a result of psychological problems affecting usually girls and young women. Appetite loss, nausea and vomiting may be provoked by painful shock, insufficient oxygenation of medulla oblongata, increased intracranial pressure, mouth infections, gastrointestinal obstruction, liver disease, kidney problems, food allergy, and some drugs. Severe thinness may end in pronounced emaciation sometimes leading to death.
Severe thinness may produce considerable harm to human organs and systems. In severe thinness experts find significant protein and vitamin deficiency against the background of extremely low caloric consumption. The losses of fat and muscles in severe thinness are explained by the fact that body uses these constituents for energy to support nervous system and heart.
Severe thinness accompanying anorexia nervosa is characterized by victim's unwillingness to keep to normal weight. About 90 % of patients with anorexia nervosa and severe thinness are girls and women aged from 12 to 25 years. Thus, many cases of severe thinness begin in adolescence. A person with severe thinness weighs no more than 85 % of normal weight range and sometimes even much less. Victims of severe thinness lose the ability to assess their weight and body proportions. They sincerely believe that their severe thinness is attractive and refuse to change eating habits. Girls with severe thinness suffer from strong fear of gaining weight. Depression and obsessive-compulsive disorder often go together with severe thinness. Five to ten percent of people with severe thinness die as a result of starvation.