Prosody and lexical accuracy in flat affect schizophrenia.

To test the hypothesis that flat affect in schizophrenia involves a motor-expressive deficiency, but not an emotional deficiency, we compared the acoustic properties of speech that are used to express emotion with the emotional content of the words. DSM-III-R schizophrenic patients were divided into flat (N=20) and non-flat affect (N=26) groups on the basis of rating-scale scores. Twenty normal subjects also were included. Subjects were recorded on audio tape as they described a happy and a sad experience for about 10 min. The recordings were analyzed acoustically for fluency and for two types of prosody: inflection and emphasis. Words from transcriptions of the recordings were sorted by content analysis software into psychologically meaningful categories; we compared 'pleasure' and 'distress' word categories. Patients with flat affect spoke with less inflection, and were less fluent. However, they were similar to the other groups in the rate at which they used 'pleasure' words to describe happy experiences and 'distress' words to describe sad experiences. The behavioral deficiency in flat affect appears to be restricted to reduced activity in communicative motor channels. Other aspects of emotion processing seem intact.