Intelligence is a set of cognitive abilities of a person, the desire to acquire new knowledge. Well-developed logical memory, purposeful thinking and high volitional activity are prerequisites for the formation of intelligence. There are two types of intelligence: practical and theoretical. Intelligence can be high, medium, or below average.

Dementia is a pathology of the intellect in the form of a persistent irreversible defect. It is manifested in the form of a complete or partial loss of the ability to process and systematize the received representations.

Oligophrenia is a congenital form of dementia (congenital underdevelopment). Oligophrenia is a non-gradient state, the aggravation of the signs of dementia can occur under the influence of additional factors (traumatic brain injury, alcoholism, substance abuse, etc.). Along with intellectual insufficiency, there are always signs of underdevelopment of the entire personality (volitional disorders, emotional, speech, motor). Causes: hereditary diseases, intoxication, infections, endocrine pathology, injuries, RH-conflict, gene deviations.

If you installed the etiology of mental retardation is talking about differentiated mental retardation.

According to the type of temperament, there are torpid (quiet) and erectile (excitable).

There are also uncomplicated (there are only signs of dementia) and complicated (with psychopathic manifestations, with psychopathic episodes, with epileptiform syndrome).

According to the degree of severity of dementia, the following forms of oligophrenia are distinguished.

Idiocy. The patient has no formed articulate speech. From the converted speech, patients perceive only intonation. Motor function is grossly impaired, basic skills are lacking, and patients are not capable of self-care. Only the unconditioned reflexes are preserved. Idiocy is often combined with gross physical pathology and deformities.

Imbecility. Abstract thinking is impossible, and there are obvious difficulties with concrete – figurative thinking. Speech is defective, develops late, vocabulary is small, grammatical structure is broken. Basic self-service skills have been formed.

Debility. A mild form of mental retardation, is characterized by the underdevelopment of abstract logical thinking, abstract generalizations. Thinking is concrete. The vocabulary and amount of knowledge are poor and do not correspond to the age norm.

Debility is classified into a light, medium, or severe degree. The diagnosis is based on clinical signs and pathopsychological tests. In mild cases, patients are able to study independently in high school, in severe cases, training in auxiliary schools is required. Patients are capable of simple independent work. Mechanical memory may be well developed, logical memory may be completely absent, or it may be weakened.