We can define use any substance use (experimental, occasional or episodic), abuse or harmful use as a substance use that is already associated with some impairment (both in terms of biological, psychological and social) and, finally, as a dependency consumption without control, usually associated with serious problems for the User. This gives us an idea of continuity, with a progressive evolution between these levels of consumption: individuals would initially for a period of use, some of them subsequently evolving to the stage of abuse and finally make some of the latter would be dependent .

The current classifications of disorders caused by psychotropic drugs provide diagnostic criteria that are general, ie regardless of the substance used to characterize abuse / harmful use or dependence. Not all drug use is due to dependence and most people who have dysfunctional use of any drug is not dependent. Recent studies have shown that the condition of harmful use of a drug not always progress to dependence.

The dependence syndrome, according to International Classification of Diseases, ICD-10 (Classification of Mental and Behavioral Disorders in the ICD-10), is described by a set of physiological phenomena, behavioral and cognitive, in which the use of a substance or a class of substances reaches a much higher priority for a given individual than other behaviors that once had value. A diagnosis of dependence should usually be made only if three or more of the following have been experienced or exhibited at some time during the previous year:

• A strong desire or sense of compulsion to consume the substance;
• Difficulties in controlling the behavior of consuming the substance in terms of initiation, termination or levels of consumption;
• A physiological withdrawal state when substance use has ceased or been reduced, as evidenced by: the characteristic withdrawal syndrome for the substance or the use of the same substance (or a closely related) with the intent to relieve or avoid withdrawal symptoms;
• Evidence of tolerance, so that increasing doses of psycho-active substance are required to achieve effects originally produced by lower doses;
• Progressive neglect of alternative pleasures or interests in favor of the use of psycho-active substance, increasing the amount of time required to obtain or take the substance or to recover from its effects;
• Persistence in substance use despite clear evidence clearly harmful consequences such as liver damage by excessive consumption of alcohol, depressive mood states consequent to periods of excessive consumption of the substance or impairment of cognitive functioning related to the drug;
• The dependent, therefore, is someone who develops a behavior that largely can not control. But there is a formula to know who among the drug users will become dependent. The land is of possibilities, risks and situations on...