Affective Disorders

Place in the classification of mental disorders

According to the nosologically oriented taxonomy developed by the Mental Health Research Center (MHRC) of the Russian Academy of Medical Sciences (based on the works of A.V. Snezhnevsky and A.S. Tiganov), all mental illnesses are strictly structured. Affective diseases are included in the first, fundamental group — endogenous mental illnesses.

In addition to affective pathology, the endogenous group also includes schizophrenia and late-onset functional psychoses (e.g., involutional depression and involutional paranoid).

Within the affective disease subgroup itself, the following forms are distinguished:

• Affective psychoses (this category specifically includes manic-depressive psychosis — MDP).
• Cyclothymia (milder mood fluctuations).
• Dysthymia.
• Schizoaffective psychoses (combining features of mood disorders and an endogenous process).

Principles of clinical taxonomy

The framework upon which any clinical classification in psychiatry is built is the syndromic characteristic of the patient's current condition.

The most critical evaluation criterion is the depth and severity of the mental impairment. Consequently, the taxonomy always draws a clear boundary between:

1. Mild borderline manifestations — traditionally encompassing various neuroses.
2. Gross mental disorders — these states are classified as psychoses (including affective and schizoaffective ones).

Distinction from stable non-processual states

Affective disorders are diseases, meaning they have a specific course and dynamics. They must be distinguished from stable mental states that have no clinical progression and, strictly speaking, are not classified as "diseases."

In psychiatric practice, two types of such stable, non-processual states are identified:

• Mental defect — an unchanging, persistent disorder that remains with a person throughout life. It is always the consequence of some past external or internal impact (e.g., traumatic brain injury, severe intoxication, stroke, or strangulation asphyxia from hanging). A classic example of a permanent defect is oligophrenia.
• Pathological development — represents persistent social maladaptation. Unlike a defect, it is caused not by a past illness or injury, but by prolonged exposure to exceptional, traumatic conditions that disrupted normal personality formation. Such conditions include irrational upbringing, imprisonment, or the influence of an antisocial peer group. A typical example of pathological development is psychopathy.

Differentiation from other disease groups

For accurate diagnosis of affective disorders, the physician must rule out pathologies from adjacent classification categories of the MHRC RAMS. Specifically, affective fluctuations must not be a manifestation of:

• Endogenous-organic diseases. These include epilepsy, as well as degenerative (atrophic) brain processes (Alzheimer-type dementias, such as Alzheimer's disease and senile dementia, and systemic-organic pathologies — Pick's disease, Huntington's chorea, Parkinson's disease). This also includes specific late-onset psychoses (acute psychoses and chronic hallucinoses).
• Exogenous and somatogenically conditioned disorders. This broad group includes vascular, infectious-organic, and exogenous-organic brain diseases, the consequences of trauma and tumors. This category also includes alcoholism, drug addiction, substance abuse, and symptomatic psychoses arising against the background of somatic infectious and non-infectious diseases or intoxications.

Class and exam questions

What else to study on this topic

• Late-onset functional psychoses (involutional depression and paranoid)
• Differences between pathological development (psychopathy) and mental defect
• Degenerative brain processes (Alzheimer's, Pick's, Parkinson's diseases)
• Exogenous mental disorders in alcoholism and drug addiction
• Symptomatic psychoses in somatic diseases

Other topics in "Chapter 18. Classification of Mental Disorders"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.