Evolution of the diagnosis and classification
For a long time, the diagnosis of sluggish (slowly progressive) schizophrenia was actively used in the domestic psychiatric school. Originally, the idea of distinguishing such mild, or latent, forms of pathology belonged to the prominent psychiatrist E. Bleuler. These conditions are characterized by an extremely slow development of the clinical picture, as well as mild expression of both positive (hallucinations, delusions) and negative symptoms.
However, in the 1970s–1980s, this term became the subject of serious political discussions due to abuses in making diagnoses. To avoid diagnostic vagueness, the modern International Classification of Diseases (ICD-10) grouped mild psychopathy-like and neurosis-like variants into a separate category: schizotypal disorder [F21].
To understand the boundaries of the disorder, it is important to distinguish it from other forms:
- Acute transient psychotic disorders [F23]: conditions lasting strictly less than one month.
- Schizoaffective disorders [F25]: occurring as recurring affective-delusional phases.
Etiology and genetic risks
Despite numerous historical theories (toxic, viral, autoimmune), none of them provides an exhaustive explanation. Today, the genetic theory is considered the most well-founded. The disease is polygenic in nature, involving a complex of genes in its development. It is important to understand that genes form only a predisposition, which is far from always realized.
Genetic risk directly correlates with the degree of kinship with the affected individual. According to the hierarchy of I.I. Gottesman (1991), risks are distributed as follows:
- Minimal risk (~1%): general population.
- Low risk (up to 5%): spouses, cousins, uncles, aunts, nephews, grandchildren.
- Moderate risk (6–13%): half-siblings, parents, full siblings, and children of one affected parent.
- High risk (~17%): siblings who have one affected parent, and dizygotic (fraternal) twins.
- Maximum risk (40–50%): children who have both parents affected, and monozygotic (identical) twins.
Neurochemical mechanisms of pathogenesis
The foundation of the disease is an imbalance of neurotransmitter systems in the brain. A single genetic defect has not yet been discovered, so the pathology is considered multisystemic.
- Dopamine system: of primary clinical interest. Dopamine receptors (primarily D2, as well as D3 and D4) are the ones blocked by antipsychotics during treatment. Conversely, dopamine agonists (e.g., mescaline) and drugs that potentiate its release (amphetamine) can provoke psychosis.
- Serotonin system: many modern drugs block 5-HT2A receptors, which helps combat negative symptoms. Serotonin derivatives (psilocybin, LSD) cause transient psychotic states.
- Glutamate: acts as the main "conductor," controlling the activity of dopamine and serotonin. A decrease in glutamatergic activity in the frontal parts of the brain is associated with the formation of negative symptoms. NMDA receptor blockers (phencyclidine) can cause both positive and negative symptoms.
- Monoamine oxidase (MAO): hyperactivity of monoamines in psychosis can be explained by a decrease in the activity of MAO, the enzyme responsible for breaking them down.
- Endogenous peptides: endorphins, enkephalins, cholecystokinins, and somatostatin also participate in the fine-tuning of the monoamine system.
Dysontogenesis and non-genetic factors
In addition to genetics, non-genetic factors are critical for the manifestation of the disorder. A key role is played by dysontogenesis—various disturbances during intrauterine and early postnatal development.
Signs of deviation from normal development are often noticeable in the premorbid (pre-illness) background even before the first manifestations of the pathology. Many patients, especially with unfavorable courses, are characterized by so-called stigmas of dysembriogenesis:
- Dysplastic constitution.
- Atypical dermatoglyphics (specific skin ridge patterns).
- Micro-anomalies of brain structure.
It is worth noting that different forms of endogenous psychoses have a distinct nature. Thus, episodic forms are genetically closer to bipolar disorder. However, early childhood forms are less frequently associated with bad heredity; they are closer to organic brain lesions and are accompanied by a pronounced neurocognitive defect with a decline in intelligence and memory.
Briefly: answers to topical questions
What clinical diagnostic criteria (symptoms) of schizotypal disorder are distinguished in ICD-10?
In ICD-10, schizotypal disorder manifests exclusively with neurotic-level symptoms, without the development of true delusions and distinct hallucinations. The following clinical manifestations are distinguished:
- Thought disorders — limited to obsessions and overvalued ideas.
- Perceptual disturbances — cenesthopathies are possible.
- Affective sphere — mood swings (subdepression, cyclothymia).
- Self-awareness — a feeling of loss of the former "I" arises (depersonalization).
- Social sphere — communication does not bring relief, the increase in negative symptoms leads to the loss of social connections.
- Insight into the condition — is usually preserved, causing painful experiences of one's own inferiority.
Which groups of psychotropic drugs, besides antipsychotics, are used for the complex treatment of schizotypal disorder?
In the cited sources, specific groups of psychotropic drugs used precisely for the complex treatment of schizotypal disorder are not specified.
For schizophrenia spectrum disorders, the sources mention tricyclic antidepressants (TCAs) and psychostimulants: they are capable of provoking an exacerbation of psychosis and therefore should be used with caution and exclusively in combination with potent antipsychotics.
Which clinical variants (forms) of schizotypal disorder are traditionally distinguished in domestic psychiatry?
In domestic psychiatry, schizotypal disorder corresponds to mild forms of sluggish (slowly progressive) schizophrenia.
According to ICD-10, schizotypal disorders [F21] include mild:
- neurosis-like variants;
- psychopathy-like variants.
To memorize the neurochemistry of endogenous psychoses, use the "GDS-M" rule: Glutamate (the conductor, low in the frontal lobes), Dopamine and Serotonin (the performers, their imbalance produces symptoms), and MAO (the cleaner, which poorly breaks down neurotransmitters).
What else to study on this topic
- Acute transient psychotic disorders (F23) and time criteria
- Schizoaffective disorders: differential diagnosis
- Neurocognitive deficit in early childhood forms of psychosis
- Stigmas of dysembriogenesis in psychiatry
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