PSYCHOSIS TOXINFECTIVA. — Mental syndromes that arise in the course of general diseases and infectious diseases not specifically localized to the nervous system, attributable to the action of autotoxins (renal insufficiency, cachexia, deficiency states, endocrinopathies, etc.) and bacterial toxins (febrile diseases in general).
Thus delimited, the p. t. correspond to Bonhoeffer’s “symptomatic psychoses” and do not include “toxic psychoses,” or psychoses from exogenous intoxications (alcohol, narcotics, occupational intoxications: phosphorus, lead, etc.), which may be approached in some pathogenic and clinical aspects. Symptomatic psychoses and toxic psychoses share a common causal basis (etiology in the broad sense of toxic origin) that is extrinsic to individual constitution; hence the designation of exogenous (or acquired, according to Bleuler) psychoses to distinguish them from endogenous psychoses (i.e., those intimately linked to constitutional factors). However, within the morbid framework provoked by a toxic agent, an undeniable—albeit diversely assessed—influence of endogenous factors is always discernible, so that not all authors agree in accepting such a definition. This interference is deduced from the small number of cases in which a symptomatic psychosis intervenes compared to the high percentage of general diseases that produce it; moreover, from the diversity of psychic pictures that the same cause can provoke and from the variety of morbid agents that can trigger the same psychic syndrome. In other words, a given traumatic, toxic, or infectious cause, under equal conditions (i.e., intensity, duration, etc.), provokes a psychosis only in some individuals (who thus appear constitutionally predisposed), and the symptoms presented by one individual can be very different from those presented by another, while the same symptoms can arise from quite distinct morbid causes: this would signify that the development and clinical manifestations of a symptomatic psychosis are widely conditioned by individual factors (constitutional predisposition). Thus, a slight febrile rise may trigger violent delirium in some, while many tolerate high temperatures without presenting any symptoms; acute alcoholic intoxication (intoxication) can manifest in very different ways (euphoria, depression, excitement, torpor), while alcoholic delirium, uremic delirium, or typhoid delirium may sometimes be indistinguishable. The influence of constitutional predisposition is even more evident from the observation in some individuals of the same psychic picture recurring several times in their lives due to different morbid agents. Sometimes a “reactive” familial predisposition can be recognized, in the sense that in several members of a family the onset of symptomatic psychoses is observed, which may even assume a similar aspect.
The role of endogenous and exogenous factors has given rise to the most diverse interpretations and classifications of p. t. and constitutes one of the central problems of psychiatry. Some authors admit an acquired predisposition developed over the course of life due to previous diseases that would have prepared the ground for symptomatic psychosis, but this is not admissible in all cases.
Bonhoeffer explains the lack of relation between cause and effect (i.e., between morbid agent and symptom) with his theory of the exogenous reaction; intoxications or infections would give rise to non-specific metabolic toxins (Kraepelin’s metastasis) relative to the initial morbid episode, toxins that would represent the direct causes of the syndromes or elective types of the exogenous reaction. The psychic pictures thus denominated are, for this reason, not pathognomonic of a specific morbid form, but are common to the entire group of exogenous psychoses and very different from those observed in endogenous psychoses (i.e., those linked to constitutional factors). The elective types of exogenous reaction, according to Bonhoeffer, are: clouding of consciousness, acute delirium, amentia, hallucinosis, amnesic twilight states, etc. The influence of endogenous factors on the development and clinical manifestations of symptomatic psychoses is, instead, according to others, sufficiently important to invalidate the classification of psychoses according to exogenous and endogenous causes, and some (Kleist) propose a classification according to the type of symptoms.
Settra has attempted a solution to the problem by proposing a classification based on both causal and symptomatic elements at the same time; he recognizes, in the psychic symptomatology provoked by exogenous causes, fundamental (or obligatory) symptoms and accessory (or facultative) symptoms. While the former would be directly caused by the morbid agent, the latter would instead derive from a pathological constitutional predisposition manifested due to the morbid agent. It should be noted that Settra’s fundamental or obligatory symptoms are the same that Bonhoeffer describes as elective in the exogenous reaction, and according to Kleist’s “symptomatic” classification would be “eccentric” symptoms. Settra’s facultative symptoms are instead those that characterize endogenous psychoses and that, according to Kleist’s symptomatic classification, would be “homonymous” symptoms.
The most frequent and important symptoms of p. t. are: disturbance of consciousness, delirium, and psychomotor alteration. These symptoms can present in various degrees and combinations, thus giving rise to the various syndromes (stuporous, delirious, amnesic, etc.) described by authors as typical of these affections. The disturbance of consciousness is usually the cardinal symptom: the patient appears “confused,” lacking attentive concentration and critical capacity, completely disoriented; associations are slowed and incorrect, and delusional convictions arise, fueled by illusions and hallucinations. The delirium is fragmentary and variable, usually with terrifying content (frightening visions, bestial shouts, etc.) and provokes a profound alteration of psychomotor mechanisms that can manifest in an increase of motor impulse up to violent agitation, or in a slowing down to total arrest. These are the symptoms that predominate in the syndromes described as “elective of the exogenous reaction” by Bonhoeffer.
The prognosis is usually linked to that of the general disease and to its cure; indeed, in the majority of cases, the disappearance of psychic symptomatology follows. Sometimes, however, psychopathic forms (post-psychotic states) of greater or lesser duration remain. Therapy must essentially be directed against the general disease.