The ability of the ego to execute its functions, to mediate between the external world, the id, and the superego effectively and efficiently, so that energy is left over for creativity and other integrative activities. Among specific functions that may be assessed in determining ego strength are judgment, reality testing, regulation of drives, defensive functions, thought processes, and object relations.
In classical psychoanalytical theory, the ability of the ego to maintain its various functions, the prime one of which is to perceive reality and adapt to it.