Apathy

A lack of interest or the attitude of indifference towards life, including social or emotional situations.

Reference:
Mann, R. S. (1990). Differential diagnosis and classification of apathy. Am J Psychiatry, 147(1), 22-30. Starkstein, S. E. (2000). Apathy and withdrawal. International Psychogeriatrics, 12(S1), 135-137.