Pathological modifications of affectivity are encountered in the course of all psychoses. They always appear early, and often before any of the other symptoms.
The principal ones are:
(a) Diminution of affectivity: morbid indifference;
(6) Exaggeration of affectivity;
(c) Morbid depression
(d) Morbid anger;
(e) Morbid joy.
In its most pronounced degree indifference involves all the emotions, as in extreme states of dementia (general paralysis and senile dementia in their terminal stages), in which it is associated with general mental deterioration. In less severe forms indifference is manifested by disappearance of the most elevated and the most complex sentiments, with conservation and often exaggeration of the sentiments of an inferior order. The altruistic tendencies are the first to become effaced, while the egoistic sentiments persist. Only the satisfaction of their material wants still concerns the patients and governs their conduct. Many take no interest during the visits of relatives in anything excepting the eatables brought to them; they eat as much as they can, fill their pockets with the rest, and leave without taking the trouble to express their thanks or even to bid their visitors good-by.
Morbid indifference may be conscious or unconscious. In the first case it is realized by the subject as a painful phenomenon. The patients often say: "I have lost all feeling, nothing excites me, nothing pleases me, nothing makes me sad." Some complain of being unable to suffer. This state, which may be called painful psychic anaesthesia, is frequent at the beginning of psychoses and sometimes persists through the entire duration of the affection (involutional melancholia, depressed periods of recurrent psychoses).
In the second case, which is more frequent, the diminution of affectivity is not noticed by the patient. Such is always the case in states of dementia.
The changes of other mental faculties, such as memory and general intelligence, are not necessarily proportionate to those of affectivity. Notably in dementia praecox it is not rare to find fairly good memory and relatively lucid intelligence coexisting with complete indifference.
Often combined with indifference, as described above, exaggeration of affectivity is encountered in most mental affections, congenital and acquired. It constitutes the basis of irritable and changeable moods and of the extreme irascibility so often seen among the psychotic and among neuropaths in general.
In psychoses it is an early symptom, appearing at times long before the other phemonema. An individual previously calm, gentle, kind, becomes disagreeable, ill-natured, violent. "He is completely changed," is a remark often made by the relatives.
Irritability is almost always associated with variability of moods.
Disorders of affectivity characterize a large and important group of cases included under the somewhat vague designation of constitutional psychopathic states. In these subjects the emotions are entirely out of proportion with their causes. The death of an animal plunges them into unlimited despair, the sight of blood brings on syncope, the most simple affairs preoccupy their minds so as to make them lose sleep. Sensitive in the highest degree, they see in everything malevolent intentions, disguised reproaches. But their sentiments, though very intense, do not last long; sorrows, enthusiasms, resentments, are with them but a short blaze.
Depression presents itself in pathological states, as it does in the normal state, in two forms: active and passive. This distinction is founded upon the presence or absence, or rather upon the intensity, of psychic pain. While in active depression psychic pain is very prominent, in passive depression it is dull, vague, scarcely appreciable. Indeed, as Dumas says, "the element of pain is not absent in passive melancholia; but is it not an acute and distinct psychic pain. It is but vaguely perceived." .