Emotion, affect and mood: a terminological introduction.

It is difficult to establish clear distinctions between emotion, affect and mood, because they belong to the same physiological dimension which may be conceived as 'background' activity'; for the purposes of research definitions should be as precise as possible. After a review of the most commonly used and sometimes contradictory definitions of these and related terms, a modified version of Janzarik's model of the 'structural-dynamic coherency' is proposed as a frame of reference for improvement in defining different 'dynamic states'. The clear distinction between emotional resonance, mood and drive for the description of pathological modifications of the background activity is discussed.