The etiological principle in psychiatry
Establishing the true cause of a mental illness in clinical practice can be extremely difficult. Events preceding the onset of the disease may turn out to be incidental factors rather than actual triggers.
Nevertheless, in the basic classification, all pathologies are divided into three major groups:
- Endogenous — arising under the influence of deep-seated internal causes within the body.
- Exogenous — developing due to aggressive external biological or physical impacts.
- Psychogenic — provoked by external psychosocial shocks.
Specifics of endogenous diseases
The group of endogenous diseases (which traditionally includes schizophrenic spectrum disorders) is characterized by a specific mode of onset. Their debut is typically spontaneous — clinicians fail to identify an objective external factor that could serve as a triggering mechanism.
A key feature of such pathologies is an autochthonous course. This means that the dynamics of the patient's condition are completely independent of external conditions: changes in weather, diet adjustments, or improvements/worsening of family and work environments do not affect the alternation of exacerbations and remissions.
Heredity plays a leading role in etiology. It is important to understand: what is transmitted from parents to children is not the disease itself, but a specific constitution (predisposition). This predisposition transforms into a real clinical picture only in a certain proportion of carriers.
Exogenous, somatogenic, and psychogenic disorders
Unlike endogenous processes, the other groups of disorders have a clear link to external impacts.
Exogenous and somatogenic factors Exogenous pathologies are caused by physical, chemical, or biological blows from the outside (traumatic brain injury, radiation, intoxications, hypoxia, severe infections). In clinical practice, somatogenic disorders are grouped here as well — psychiatric disorders developing against the background of underlying somatic illnesses (tumor processes, vascular atherosclerosis, endocrine disorders, collagenoses). The symptomatology of these two subgroups is identical because brain tissue reacts stereotypically to hypoxia or toxic poisoning, regardless of the primary source.
Psychogenic diseases These disorders develop against the background of intrapersonal conflicts, family dramas, social problems, and prolonged emotional stress. Their course is 100% tied to the stressor: as long as the conflict is active, symptoms escalate; as soon as the problem is resolved, the condition normalizes. The prognosis in this group is the most favorable, and complete recovery is often possible.
Organic and functional lesions
Based on the presence of a physical disease substrate, conditions are divided into two categories:
- Organic disorders. Characterized by clear structural brain damage. The clinical picture is dominated by persistent negative symptoms, primarily profound intellectual and memory impairments. This includes all exogenous and somatogenic pathologies, as well as some endogenous ones (e.g., epilepsy and atrophy-related lesions).
- Functional disorders. Diagnostic imaging and examinations reveal no structural changes in the brain. All psychogenic diseases fall into this group.
Dynamics and variants of disease processes
From a nosological standpoint, only a pathology with distinct dynamics can be termed a disease (process): it has a clear onset, a developmental period, and a logical outcome.
Main variants of the course:
- Acute: occur as a single episode in the patient's lifetime.
- Protracted and chronic: last for years, practically incurable, and prone to constant relapses.
- Progressive: the severity of clinical manifestations steadily increases.
- Regressive: a clear, stable attenuation of symptoms is observed.
- Paroxysmal: periods of exacerbation alternate with qualitative remissions.
- Phasic (circular): attacks succeed one another, demonstrating directly opposite symptoms.
- Fluctuating (undulating): the severity of the disease varies significantly, but full remissions do not form (often associated with temporary hemodynamic changes, e.g., in cerebral atherosclerosis).
Briefly: answers to topical questions
What symptoms dominate the clinical picture of organic mental disorders?
The clinical picture of organic mental disorders is dominated by persistent negative symptoms grouped under the concept of psychoorganic (encephalopathic) syndrome. The basis of the clinical picture is the Walter-Bühl triad:
- Memory impairment — memory decline, various types of amnesia and paramnesia.
- Intellectual impairment — diminished judgment and reasoning capabilities with the loss of late-acquired skills.
- Affective disorders — emotional instability and rapid mood shifts.
Diagnostic signs also typically include Bonhoeffer's exogenous-type syndromes: asthenic syndrome, altered states of consciousness, hallucinosis, epileptiform paroxysms, Korsakoff's amnestic syndrome, and dementia.
Which diseases are classified as functional mental disorders?
Functional mental disorders refer to disorders characterized by the absence of structural brain changes. Sources classify the following among them:
- Psychogenic disorders, including neuroses and reactive psychoses.
- Schizophrenia.
- Manic-depressive psychosis.
Psychopathies are also described as functional disorders; however, they are stable states without a progressive course and are not classified as diseases.
Which specific diagnoses are included in the group 'Schizophrenia, schizotypal and delusional disorders' according to ICD-10?
F2 category in ICD-10 includes schizophrenia proper, other delusional psychoses, and related states. Specifically, sources mention the following diagnoses in this group:
- Schizophrenia (F20) — the most malignant typical variants lasting longer than 1 month.
- Schizotypal disorder (F21) — sluggish (sluggishly progressive) schizophrenia manifested exclusively by neurotic-level symptoms without true delusions.
- Schizoaffective disorder (F25) — diagnosed when symptoms of schizophrenia and affective disturbances (mania or depression) are of equal significance.
Also included in this group are similar psychoses lasting less than 1 month.
What are the main clinical forms of schizophrenia?
Sources classify the following as typical forms of schizophrenia:
- Simple.
- Paroxysmal.
- Demented.
- Delirious.
- Senile.
Clinical variants are described separately:
- Paranoid schizophrenia — characterized by delusions and hallucinations.
- Catatonic schizophrenia — characterized by catatonic syndrome presenting as stupor or excitement.
- Hebephrenic schizophrenia — classified among malignant variants.
"Endo means inside, exo means outside, psycho means in the soul." This basic rule helps to quickly classify the cause of a disorder.
Class and exam questions
What is the main difference between somatogenic and exogenous disorders?
There are no fundamental differences in symptomatology, since the brain reacts identically to damaging factors. Somatogenic disorders are caused by internal bodily diseases (atherosclerosis, endocrinopathies), but in practice they are classified as exogenous.
What does "autochthonous course" of a disease mean?
This is a course where the deterioration or improvement of the mental state occurs spontaneously, without any connection to external factors (weather, stress, diet).
Which disorders are classified as functional?
Functional disorders refer to pathologies where there are no structural changes in the brain. Primarily, these include all psychogenic diseases.
What else to study on this topic
- Specifics of negative symptoms in organic brain lesions
- Distinction between phasic (circular) and episodic courses
- The role of hereditary constitution in the development of endogenous processes
- Mechanisms of cerebral atherosclerosis influence on the undulating progression of disorders
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Other topics in "Chapter 18. Classification of Mental Disorders"
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