Dependence on psychotropic substances, that is capable of altering the balance of the central nervous system, is defined by the "World Health Organization as" a psychic and sometimes physical state, deriving from the interaction with a substance, which determines changes in behavior and the need to take this, to obtain the same psychic effects and avoid the withdrawal syndrome ".
The pictures of real addiction are conditioned by the presence of the phenomena of tolerance, abstinence, compulsive behavior of taking the substance of abuse (craving) and relapsing behavior (relapse in use).Definition
The concept of addiction to a substance includes the set of disorders of reasoning and body functioning present in people who use it continuously.
The definition of addiction to a substance provides for the presence, in the person who uses it, of at least three of eight typical elements:
- first, the craving, formerly called psychological addiction. It is an intense desire to experience the effects of a psychoactive substance again. Desire is the cause that leads to using a substance again (relapse) even after long periods of abstinence
- second, physical or psychological dependence, which refers to a state of physical and / or psychological dependence and the consequent, possible, abstinence from the substance
- third, the priming, that is to say the exposure to a substance of abuse previously taken which can lead to a rapid recovery in the use of the substance in an even more intense way
- fourth, relapse, or the resumption of the use of a psychotropic substance (pharmacologically active, capable of modifying the psycho-physical state of a subject) after a period of abstinence. The environmental stimuli (people, places or things associated with the use of the substance in past) and stress can trigger an intense desire to take the substance and cause a relapse
- fifth, the reward, a stimulus that the brain interprets as positive and, therefore, to be achieved
- sixth, awareness raising, to be understood as the increase of the expected effect after the repeated administration of a psychotropic substance. Sensitization is one of the neurobiological mechanisms involved in craving and relapse
- seventh, the abuse of substance, phenomenon characterized by repeated negative consequences that cause damage to health: inability to lead a life with regular rhythms, use of the substance in physically dangerous situations, legal, social and interpersonal problems related to the use of the substance
- eighth, withdrawal syndrome, or the set of signs and disorders (symptoms) caused by the abrupt withdrawal or reduction of the use of a psychotropic substance. Or, the consequences of the action of a substance used in a possible cessation treatment. This syndrome can be one of the causes of craving or short-term relapse
Physical tolerance and dependence reflect the body's adaptation to the effects of a psychotropic substance, while the other criteria define the uncontrolled desire to consume that substance. However, tolerance and physical dependence are not necessary and sufficient conditions to ascertain (diagnose ) an addiction.
Knowing the mechanisms that lead to addiction is very difficult because they are very complex and include both cellular and molecular, behavioral and social mechanisms.
The pharmacological and physicochemical properties of the substances of abuse are important factors in the onset of addiction and abuse since the substances can be taken in different ways based on their specific characteristics:
- ability to dissolve in fats (fat solubility), property that increases the possibility of the substance to pass through the blood brain barrier, a structure that regulates the passage of substances in the brain to protect it
- ability to dissolve in water, a property that facilitates the possibility of administering the substance into a vein
- volatility, property that favors the possibility of inhaling the substance in the form of vapor
- resistance to heating, property that favors the possibility of smoking the substance
These characteristics favor the rapid effect of the substance and its intensity, which is why substances that reach high concentrations in the brain are generally preferred. For this, heroin is preferred to morphine and the smoke of the crack (cocaine hydrochloride in sodium bicarbonate which allows the formation of cocaine base) is preferred to nasal (intranasal) administration of cocaine (in the form of hydrochloride salt). Furthermore, any short stay (half-life: the time required to reduce the bioavailability by 50%) of the substance in the body (for example, that of heroin) produces sudden and intense withdrawal crises compared to substances that have a "long half-life. (such as methadone).Diagnosis
To ascertain (diagnose) dependence on a substance, at least three of the following characteristics must be present:
- substance tolerance
- withdrawal disorders
- use of the substance in increasing quantities and for longer and longer periods
- persistent desire and unsuccessful attempts to reduce or control its consumption
- continuous research of the substance
- alteration of a normal lifestyle, due to the consumption of the substance
- continued use of the substancedespite health, economic and social problems
American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 4. ed. The American Psychiatric Association: Washington, DC, 1994
Hendricks P S, Delucchi K L, Hall S M. Mechanisms of change in extended cognitive behavioral treatment for tobacco dependence. Drug and Alcohol Dependence. 2010; 109(1-3): 114-119In-depth link
NIH - National Institute on Drug Abuse (NIDA). The Science of Drug Use and Addiction: The Basics (English)
Higher Institute of Health (ISS). OssFAD - Smoke, Alcohol and Drugs Observatory
European Monitoring Center for Drugs and Drug Addiction (EMCDDA) (English)