Psychotropic substances: classification, dependence, psychoactive substances

Q: Which neurotransmitter systems are involved in the formation of dependence syndrome (reward systems)?

Neuromediator mechanisms are involved in the formation of dependence syndrome and activation of the reinforcement system. - Dopaminergic system — drugs stimulate dopamine release in the nucleus accumbens; with repeated use, mediator deficiency develops, and dopamine synthesis is compensatorily increased. - Catecholaminergic mechanisms — during the formation of dependence, synthesis of dopamine and norepinephrine is increased, and catecholamine turnover is accelerated. - Opiate system — µ-opioid receptors have been described in the reticular formation and limbic system; endogenous ligands — endorphins and enkephalins — are localized in the "pleasure centers." - In chronic alcoholism, adaptive changes develop: the activity of the excitatory glutamatergic system increases, while the inhibitory GABAergic system is suppressed.

Classification and types of psychoactive substances

In pathophysiology, all psychoactive substances (PAS) are divided into three main categories:

Psychotropic drugs
Narcotic drugs
Substances of abuse (toxicomanic substances)

Each compound is viewed from two perspectives: pharmacological (medical use for treating pathologies) and social/legal (non-medical use, which is socially dangerous and punishable).

Psychotropic drugs directly affect mental status and are actively used in the treatment of psychiatric disorders. However, some of these drugs can provoke the development of dependence and addiction with uncontrolled use.

Groups of psychotropic drugs

This category of medicinal and pharmacological drugs includes several key groups:

Antidepressants
Antipsychotics
Psychostimulants
Sedatives
Tranquilizers

All of them exhibit a pronounced affinity for central nervous system structures, alter the psychophysical status of the organism, and require strict medical supervision due to the risk of developing addictive states.

Test your knowledge on this topicTasks from the "Pathophysiology" course bank — instant answers and explanations.

Signs of drug addiction and substance abuse

These pathological conditions are classified as typical forms of psychosomatic pathology. Their key signs include:

Persistent pathological craving for the repeated consumption of the substance.
Increase in the doses taken (increased body tolerance).
Development of physical and psychological dependence.
Development of abstinence syndrome (withdrawal syndrome) upon cessation of substance intake.
Persistent pathological personality changes.
Complex of neurotic, psychiatric, autonomic, and somatic disorders.

Causes and risk factors

Repeated use of psychoactive substances is provoked by a complex of conditions divided into three groups:

Social: stress, social instability, informational overloads, low material standard of living, environment characteristics, and national customs.
Psychological: poor social adaptability and weak type of higher nervous activity (HNA).
Biological: genetic predisposition to PAS use.

Briefly: answers to topical questions

What are the pathophysiological mechanisms of tolerance development to psychoactive substances?

The development of tolerance to psychoactive substances is due to several mechanisms.

Enzyme activation — activation of PAS metabolism enzyme systems occurs, leading to accelerated destruction of the substance (for example, barbiturates cause autoinduction and acceleration of their own metabolism).
Receptor desensitization — decrease in receptor sensitivity to the substance.
Membrane alteration — the composition and structure of neuronal biological membranes change. An excess of cholesterol and higher fatty acids accumulates in the lipid phase, which reduces the mobility of receptors in the membranes.

Which neurotransmitter systems are involved in the formation of dependence syndrome (reward systems)?

Neurotransmitter mechanisms are involved in the formation of dependence syndrome and activation of the reward system.

Dopaminergic system — drugs stimulate dopamine release in the nucleus accumbens; upon repeated administration, a deficit of mediators develops, and dopamine synthesis increases compensatorily.
Catecholaminergic mechanisms — during the formation of dependence, the synthesis of dopamine and norepinephrine increases, and catecholamine turnover accelerates.
Opiate system — µ-opiate receptors are described in the reticular formation and limbic system; endogenous ligands — endorphins and enkephalins — are localized in the "pleasure centers".
In chronic alcoholism, adaptive changes develop: the activity of the excitatory glutamatergic system increases and the inhibitory GABAergic system is suppressed.

What is the pathophysiological difference between the mechanisms of psychological and physical dependence?

The difference between psychological and physical dependence lies in the mechanisms of their formation.

Type of dependence	Pathogenesis
Psychological dependence	Arises due to the depletion of neurotransmitter stores (deficiency of dopamine and other catecholamines) when PAS concentration decreases, which causes psychological discomfort, depression, and the formation of an irresistible need (craving) for stimulation.
Physical dependence	Forms as a result of compensatory enhancement of neurotransmitter synthesis and breakdown. Upon cessation of PAS intake, the rate of catecholamine synthesis remains high, while utilization decreases, leading to excessive mediator accumulation and the development of withdrawal syndrome (somatic and autonomic disorders).

How to memorize

PsychoTropic = Touch Tissue (nervous tissue).

Class and exam questions

What is the difference between narcotic drugs and toxic substances?

Narcotic drugs are officially included by competent authorities in the list of substances prohibited for non-medical use. Toxic substances also have a specific effect on the CNS, but are not included in this official list.

What is the difference between drug addiction and substance abuse (toxicomania)?

Drug addiction is caused by agents from the official list of narcotics. Substance abuse develops with the abuse of other substances not classified as narcotics, including ethanol and certain medications.

What is withdrawal syndrome in psychoactive substance use?

This is a withdrawal syndrome that develops upon cessation of psychoactive substance intake and is accompanied by a complex of psychiatric, neurotic, autonomic, and somatic disorders.

What groups of psychotropic agents exist?

This group includes antidepressants, antipsychotics, psychostimulants, sedatives, and tranquilizers.

Something unclear? Ask the AIThe AI tutor has read the material on "Psychotropic substances" and will explain it in simple terms.

What else to study on this topic

Classification of narcotic drugs (opiates, barbiturates, cocaine, marijuana, hallucinogens)
Characteristics of substance abuse agents (chemical reagents, household chemicals, ethanol)
Etymology and general properties of drugs
Motives and goals of non-medical use of psychoactive substances
Biological, psychological, and social factors in the development of dependence

Master the entire topic in the "Pathophysiology" course

This is a summary. The course covers everything tested in classes and exams.

Complete study guide on the topic «Psychotropic substances» and another 4,913 pages of the subject
Assignments and quizzes after every topic — just like in a colloquium
AI tutor answers questions on the topic anytime
135 video lessons on the subject

Open full review Subject curriculumfrom 599 ₽ per month

Psychotropic substances