Apathy is a quantitative reduction of interest, motivation and the initiation and persistence of goal-directed behavior, where often the accompanying emotions, thoughts, and social interactions are also diminished. The individual is typically non-reactive to provocations, positive or negative, and appears to not care. Distinguished from lethargy which involves lack of physical or mental energy. The phenotype is Apathy (HP_0000741). Also known as: Lack of feeling, emotion, interest, Lack of feeling, emotion, interest, motivation, initiation, State of indifference.