Apathy is an emotional state characterized by a lack of emotion or interest either toward a particular subject or toward all elements of one's life. Characteristics of apathy include a lack of passion and motivation, the absence of excitement or interest in any particular aspect of one's life, and a lack of concern for one's emotional and social well-being. Such a condition may be purely psychological in origin, or it may originate from a variety of neurological disorders. It can also be caused by the regular use of powerful mind-altering drugs.
The modern use of the term "apathy" started during World War I. Soldiers who returned from the war after experiencing the horrors of trench warfare, endless shelling, and, in many cases, watching friends and companions die became emotionally disconnected and had little interest in their own lives. Various forms of trauma, such as witnessing a horrific crime or fighting in a war, can lead to this lack of emotion. People returning from such experiences often find that nothing seems to matter in comparison to whatever it was that they experienced or witnessed. There is no simple cure for the indifference caused by trauma, though various forms of therapy are able to help people in some cases.
Apathy is commonly one of many symptoms of a larger psychological or neurological disorder; treating the disorder can sometimes alleviate the feelings of indifference. Such conditions include Alzheimer's disease, schizophrenia, bipolar disorder, and hypothyroidism. Depression is also commonly characterized by indifference and a lack of emotional engagement with people and activities, though the connection between depression and apathy has not been deeply explored. Similar symptoms have also been connected to the use and abuse of powerful mind-altering drugs such as cocaine and heroin. Whether through physical effects on brain chemistry or through purely psychological effects, users of such drugs sometimes find that they care very little about all elements of their lives that are not connected to the substance to which they are addicted.
The term is also commonly used in the social and political sciences as well. "Voter apathy," for instance, describes a condition in which a significant part of a population chooses not to vote because they are not concerned with the outcome of an election. People may choose not to vote because they feel that their votes have little chance of significantly affecting the outcome of the election or that the outcome of the election is insignificant.