Speech rate as a measure of short-term variation in depression.

Experimental investigation of the state of depression is at present hindered by the lack of simple, objective, repeatable measures of components of the state. Covariation between self-report measures of affect and simple measure of speech rate was investigated in a series of studies of both clinical and normal subjects, using single-case and group designs. Slowing of speech was significantly and substantially correlated with self-reports of increased unpleasant affect in certain situations. This suggests that the speech measure may usefully reflect a behavioural component of a state of retarded-type depression.