DEPRESSION in the psychic sphere manifests itself by the presence of psychic pain (psychalgia), by slowness of emotive reaction and of intellection, and by the predominance of fear, grief, and other negative emotional states. This complex mental state is usually accompanied by corresponding physical symptoms—general debility, reduced muscular strength, slowness of visceral functions, and retarded metamorphosis. The features are relaxed and passive; the posture sluggish, indifferent, or cataleptoid; the animal appetites are reduced. It is seldom that the entire economy does not sympathize with the psychic state. In exceptional cases some emotions are abnormally active, as in hypochondriasis; or there may be abnormally active muscular movements, as in melancholia agitata. Usually, depression is a part (a fundamental part, however) of a more complex symptom group, as in hypochondriasis, melancholia, hysteria, the prodromal stage of mania or paralytic dementia, etc.; but sometimes it constitutes a so-called disease—melancholia sine delirio. Although depressed subjects often appear indifferent to their surroundings, and react slowly or not at all, it must not be supposed that their emotions are not subjectively active. They are often abnormally so, and psychic hyperæsthesia coexists with psychalgia. No anatomical seat can be assigned to the processes which constitute this state and the following; their psychic mechanism is unknown.
EXALTATION, or abnormally great mental activity (including emotions), so-called psyclampsia, manifests itself by a pleased or happy subjective state, by increased reaction to external stimuli, by unusually abundant and rapid ideation, and by a corresponding increase of somatic activity, as shown by apparent (?) excess of muscular power, of circulation, of visceral activity, and of the appetites. The entire being, in certain cases, becomes endowed with additional capacity and power. In the mental sphere this over-activity easily passes into incoherence and verbal delirium, while in the physical sphere it may translate itself into violence. Clinically, exaltation may show itself as an independent morbid state, known as mania sine delirio. It more commonly appears, with other symptoms, in the shape of ordinary mania, of delirium tremens, of dementia paralytica, etc. Exaltation often follows morbid depression, and these two states sometimes alternate for years (circular insanity). Exaltation, even when accompanied by violent muscular action, must not always be considered an evidence of increased nervous power. On the contrary, it is often a result of irritable weakness, and as such indicates a tonic and restorative medication.
ILLUSIONS.—By illusion is meant the result of malinterpretation of an external impression by disordered sensorial or cerebral apparatuses. All of the special senses and the common sensory nerves may be the media of illusions, but they more commonly manifest themselves in the visual and auditory spheres. A few examples will best illustrate the exact meaning of the term. An insane person mistakes a casual visitor for his brother or father: he fancies that a piece of furniture is a flowering shrub or a threatening animal; another patient will declare that the food in his mouth tastes of a particular poison; still another, having pains in the night, solemnly avers that he has been beaten or cut, etc. A real impression is made upon the centres for vision, taste, and common sensation, but it is wrongly interpreted or appreciated. The exact mechanism of illusions escapes our present means of analysis: the peripheral apparatus or the perceptive centre may be disordered; probably, in most cases, the latter. This is borne out by the fact that in many insane the illusions are in harmony with the delusions present in the mind, and then they are nearly akin to hallucinations. The word illusion is sometimes employed as synonymous of delusion, but this is an abuse of terms to be avoided. Healthy persons are subject to illusions, but the error is quickly corrected by more careful observation by the same sense, or by the use of others. The state of intoxication by cannabis indica (hasheesh) presents numberless illusions of all the senses, together with hallucinations.
HALLUCINATIONS.—By this term is designated the result of the projection into the external world, through nerves of common or special sensations, of formed sensations which arise in a disordered sense-apparatus or nerve-centre; or, in more popular language, it may be said to mean the perception of non-existent objects or impressions, creations of the imagination. Examples: Disease (sclerosis) of the posterior columns of the spinal cord irritates the roots of the sensory nerves, the result being pain at the periphery in the parts connected with the affected segment of the cord. So objective and real do these peripheral pains seem that if the patient's mind be weakened he may assert that they are due to his being beaten, stabbed, or bitten by some one or by an animal. After amputation, the absent member is long perceived by the subject, often with startling distinctness, and even after the sensation has passed away it may be brought back by faradizing the nerve-trunks above the stump. The patient may hear voices, music, or simple sounds when in reality there is silence, or he may be surrounded by imaginary images or plagued by hallucinatory smells and tastes. Hallucinations may also arise in the distribution of optic nerves.
Besides common hallucinations with their seeming reality and objectivity, we admit others which are less vivid, which do not startle or frighten the subject, and which are simply the outward projections of the patient's own thoughts (delusions). The subject of persecution by imaginary enemies may see around him the faces of his pursuers with appropriate expressions, or hears their insulting or threatening remarks, as outward plastic reproductions of his thoughts; but the patient himself recognizes the want of actual objectivity and clearness in these images. These we call, after Baillarger, psychic hallucinations or pseudo-hallucinations. Similar phenomena are observed in some sane persons under excitement and betwixt sleep and waking.
The mechanism of hallucinations is partly understood, and may be stated as follows: In some few cases a real disorder or defect in the peripheral sense-organ may give rise to false projections; for example, a tinnitus may become transformed into a distinct voice, a scotoma may be the starting-point of false pictures of a man or animal. The simpler hallucinations of pain, cutaneous, muscular, and visceral sensations may originate in irritation of the nerve-trunks (as where the nerves of an arm-stump are faradized and the patient feels his hand with fingers in motion). But the general or common genesis of hallucinations is in disordered states of nerve-centres, those for common sensations and the special centres or cortical areas in the brain. Thus, a morbid irritation of the cortical visual area or sphere will give rise to abundant hallucinations of sight; irritation of the auditory sphere to hallucinations of hearing, as sounds and voices, etc. It must be borne in mind that, however pathological hallucinations may be, they arise from the operation of a fundamental physiological law. In health we constantly refer our sensations or transfer them into the external world, thus creating for ourselves the non-Ego. All terminal sensory nerve-endings receive only elementary impressions or impulses from external agencies, and these are perceived and conceived as images, formed sounds, etc. in the appropriate cortical centres; then by the law of reference of sensations these elaborated, idealized conceptions or pictures are thrown outward again and contemplated as objective. In this physiological mechanism lies the kernel of truth which is included in idealism.
Hallucinations may occur without derangement of mind or impairment of judgment. Many instances are on record of transient or permanent hallucinations of various senses in perfectly healthy persons who were fully aware of the unreal character of what they saw or heard. Being of sound mind, they were able to make the necessary correction by reasoning or by the use of other senses. In very many forms of insanity hallucinations are prominent, though they also occur in quasi-sane conditions, as in hypochondriasis, hasheesh, belladonna, and opium intoxication, the stage between sleeping and waking, etc. As long as the subject is able to correct the false projections by reason or by the use of other senses he is considered sane.
Hallucinations are sometimes the cause of acts by the insane, some of them violent and even murderous actions. Hallucinations of sight and hearing are especially prone to lead to assaults, murders, etc. The occurrence for any length of time of acoustic hallucinations in insanity is accounted of bad prognosis.
DELUSIONS are synonymous, in a popular way, with false beliefs. Thus, we often speak of eccentric opinions, of fanatical or extravagant creeds, as delusions. In a certain sense probably all mankind cherish innumerable delusions. In a strictly medical and medico-legal sense, however, the term is applied only to false beliefs in respect to clearly-established, indisputable facts. Thus, a man who believes in Spiritualism or even in metempsychosis, or in the divinity of a certain personage, is not medically deluded; whereas, one who believes that a bare court is a flowering garden or that he himself is divine is deluded. The essential element in the conception of delusion is belief or conviction on the patient's part; and that is why delusions mean that the psychic functions are deeply and seriously impaired. Delusions may be conveniently divided into ideal and sensorial.