[The concept of mood in psychology].

The concept of mood is complex and difficult to establish. It reflects a moving notion that cannot be easily grasped. It has always been a fundamental concept in the history of philosophy and medicine. The origin of mood relies on the theory of the four humours: blood, phlegma, yellow and black bilious. Mood can be balanced by the equilibrium of these four liquids. Mood is also difficult to define because one's judgment depends on the perception of mood in other people. It is a highly subjective concept which is backed by personal references. Mood can be expressed with different tonalities. Its panel of expressions can likely explain the different definitions and analysis of this notion. The first part of this report tends to clarify the definition of mood regarding emotion, feeling or affect. Emotion is an instantaneous perception of a feeling. Affect corresponds to a freudian notion of drives. In the second part different conceptions of mood in psychology are treated. Some of them have been derived from philosophical conceptions of mood e.g. the cognitive theory and ethological conception. Others are based on the pathological model of manic depressive psychosis e.g. phenomenological and psychoanalytic views of mood theory. Moreover this analysis will attempt to show the interest of psychological tests to confirm mood troubles or to substantiate a clinical diagnosis of mood disorders. The conception of mood in cognitive psychology is derived from the analysis of emotion. Mood is considered as a group of persisting feelings associated with evaluative and cognitive states which influence all the future evaluations, feelings and actions.(ABSTRACT TRUNCATED AT 250 WORDS)