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Psychotropic Substances

For medical students2 min readUpdated 2026-10-10

Psychotropic substances are compounds with high affinity for neural tissue that can alter human mental status. A single dose alters the psychophysical state, whereas systematic use causes persistent psychological and physical dependence.

Target TissueNeural tissue (high affinity)
Main GroupsAntidepressants, antipsychotics, tranquilizers
Risk of UseDevelopment of dependence and addiction
Aspects of UsePharmacological and legal

Classification and Types of Psychoactive Substances

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

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

Psychotropic agents directly affect the psyche 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 Agents

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

  1. Antidepressants
  2. Antipsychotics (neuroleptics)
  3. Psychostimulants
  4. Sedatives
  5. Tranquilizers

All of them exhibit 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.

Signs of Substance Dependence and Toxicomania

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

Causes and Risk Factors

Repeated use of psychoactive substances is triggered by a combination of conditions divided into three groups:

Mnemonic

PsychoTropic = Touches Tissue (neural tissue).

Frequently asked questions

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

The development of tolerance to psychoactive substances is driven by several mechanisms.

  • Enzyme activation — activation of substance-metabolizing enzyme systems occurs, leading to accelerated drug breakdown (e.g., barbiturates cause auto-induction and accelerate their own metabolism).
  • Receptor desensitization — reduced receptor sensitivity to the substance.
  • Membrane alterations — the composition and structure of neuronal biological membranes change. An excess of cholesterol and higher fatty acids accumulates in the lipid phase, which decreases receptor mobility within the membranes.
Which neurotransmitter systems are involved in the formation of dependence syndrome (reward pathways)?

Neurotransmitter mechanisms participating in dependence syndrome formation and reward pathway activation include:

  • Dopaminergic system — drugs stimulate dopamine release in the nucleus accumbens; repeated use leads to neurotransmitter depletion, while compensatory mechanisms upregulate dopamine synthesis.
  • Catecholaminergic mechanisms — dependence formation increases the synthesis of dopamine and norepinephrine, accelerating catecholamine turnover.
  • Opioid system — mu-opioid receptors are described in the reticular formation and limbic system; endogenous ligands—endorphins and enkephalins—are localized in "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 their formation mechanisms.

Type of DependencePathogenesis
Psychological DependenceArises from the depletion of neurotransmitter reserves (dopamine and other catecholamine deficit) when psychoactive substance concentration drops, causing psychological distress, depression, and an overwhelming craving for stimulation.
Physical DependenceForms as a result of compensatory upregulation of neurotransmitter synthesis and turnover. When substance intake ceases, the rate of catecholamine synthesis remains high while clearance decreases, leading to excessive neurotransmitter accumulation and the development of withdrawal syndrome (somatic and autonomic disorders).
What is the difference between narcotic substances and toxic substances?

Narcotic substances are officially listed by competent authorities as prohibited for non-medical use. Toxic substances also exert specific effects on the central nervous system, but are not included in this official list.

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

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

What is withdrawal syndrome during psychoactive substance use?

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

What are the existing groups of psychotropic agents?

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

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