ASTHENIA, lack or loss of strength, a condition in which the body lacks or has lost strength either as a whole or in any of its parts. General asthenia is found in certain individuals with a characteristic physical build. They are thin, have small bones, underdeveloped musculature and are subject to neurotic affections. General asthenia occurs in many chronic wasting diseases such as anaemia and cancer. It is probably most marked in diseases of the adrenal gland, where it dominates the whole picture. Asthenia may be limited to certain organs or systems of organs. Thus there is asthenopia, which is characterized by ready fatiguability of vision, and myasthenia gravis, in which there is progressive in crease in the fatiguability of the muscular system until death results from inability of the heart muscle to continue its work. In neurasthenia and psychasthenia there is a strong subjective sense of fatigue in the absence of real weakness.