HUMOUR (Sentimental Tone, Mood). - A particular equilibrium of the sphere of the deepest feelings (v.) and of the affective state of consciousness (thymopsyché) capable of imparting to the entire personality of the subject a tone of pleasant satisfaction (serenity, cheerfulness) or of painful dissatisfaction (sadness, ill humour).
Mood, although it must be distinguished from temperament (v.) and from character (v.), is closely connected with these elements of the personality, particularly with the equilibrium of the conditions of metabolism, with endocrine functionality, with the complex of cenesthetic sensations (v. CENESTHESIA), with the variation of the vegetative and animal neurotone, and with the neuro-psychological and moral state of the subject.
Mood, even in the normal individual, in relation to the sum of organic variations and to the repeated interferences of the external environment, in the form of pleasant or unpleasant stimuli, undergoes continuous variations, orienting itself toward the aforementioned state of dissatisfaction or of satisfaction. In the absence of unpleasant tensions arising from the present state, from the memory of the past or from worry about the future, the mood is serene, attuning itself toward a sense of euphoria; in the opposite case, the tone turns toward melancholy.
Within the limits of normality, stimulus-events succeed in disturbing the mood only if they attain a determined intensity and duration; between these two elements there must coexist a relationship of proportionality. On the other hand, every stimulus, after a certain limit, not well definable, ceases to be effective, leading first to a dulling and then to the total disappearance of the affective reaction.
The different individual types present a quite different manner of orienting the mood in relation to the internal and external causes that tend to produce and modify it. While some, owing to the scant resonance of their affective life (hypothymic subjects), are little subject to variations of mood, others (hyperthymic subjects), endowed with vivacious affectivity, easily and for a long time undergo modifications and disturbances of the affective equilibrium of consciousness. Among these individuals with vivacious affectivity there exist individuals in whom the reactivity of mood can manifest itself indifferently in the two opposite directions of cheerfulness and sadness (poikilothymic or emotionally labile); such lability is present in particular in hysterics, in the so-called lunatics, in constitutional spasmophiliacs, in the meteorolabile (at the mercy of meteorological variations), in the cycloids or cyclothymics of Kretschmer. Other individuals, instead, more easily slip into a determined constant tone of mood, whether this be in the direction of serenity or of ill humour, from which they are with difficulty moved by contrary stimuli (dysphoric or euphoric hyperthymics).
When the conditions of mood present degrees clearly beyond those compatible with the extreme normal limits of fluctuating variability, whether in intensity or in duration or form, one passes into the abnormal field of mental illnesses or psychoses (mania or melancholy of the affective psychoses [v.]); here the grave alterations of mood are accompanied by psycho-sensory disturbances of the type of delusions and visual and auditory hallucinations.
The lack of stability of mood, its easy variation under the action of stimulus-events of scant importance, constitutes a strong impediment to a normal unfolding of the cognitive and volitional activity of the subject, and while on the one hand it requires a stronger impulse for the fulfilment of one's duty, it can, beyond determined limits of intensity of the defect, diminish moral responsibility. By degrees, one can thus reach the conditions of psychopathic personalities (v.) or of the various mentally ill: in such an eventuality the moral judgment formulated for them holds.
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