Definition of Flat affect

Flat affect: A severe reduction in emotional expressiveness. People with depression and schizophrenia often show flat affect. A person with schizophrenia may not show the signs of normal emotion, perhaps may speak in a monotonous voice, have diminished facial expressions, and appear extremely apathetic. Also known as blunted affect.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=26293
Last Editorial Review: 6/14/2012