Drugs capable of creating dependence are called drug addiction and are characterized by being foreign substances to the body that, except for alcohol, are not used as food and that must be eliminated after a series of biotransformations. They act in very low doses on the brain.
The terms narcotic and narcotic are used to refer generally to illegal drug addicts and differentiate them from legal ones (such as alcohol and tobacco). This could be a first classification of drugs in terms of their legality, but it is a classification that is not established according to scientific criteria, but of a social, cultural and even religious nature.
To define drug dependence, the WHO established a distinction between physical dependence and mental dependence:
- The physical dependence: shows physical disturbances when you stop taking the drug. They constitute the withdrawal syndrome (or "mono" typical of opiates.
- The psychological dependence: the need to regularly take the drug for a pleasant affective state (pleasure, welfare, etc.) or for not having an unpleasant affective state (boredom, shyness, stress, etc.).
Recent research has shown that it is not correct to distinguish between physical and mental dependence, since drugs such as cocaine, tobacco or cannabis also produce certain biochemical alterations in the brain, which is why they also create physical dependence. It has been proven that dependence on cocaine can be much greater than that on heroin.
Thus, from a physiological point of view, drug addiction can be defined as a mental state associated with a series of alterations in brain neurotransmission that, although reversible, can lead to other types of chronic disorders.