Psychoactive substances, or drugs, are all products that act directly on the brain and modify the behavior, moods, perceptions and mental activity of users
Psychoactive substances can be legal, such as alcohol or tobacco, or illegal, such as cocaine, methamphetamine, heroin or fentanyl. Cannabis use may or may not be legal, depending on the country or jurisdiction.
In most countries of the world, addiction is a major public health problem with multiple repercussions (health, medical and social). According to the World Drug Report (2022) the number of deaths directly or indirectly related to drugs is estimated at 490,000 in 2019 alone, with an increase of 17.5% since 2009
 World Drug Report 2022 – UNODC
 Questionnaire adapted from the DSM, Diagnostic and Statistical Manual of Mental Disorders (5th edition) – According to the DSM, a substance use disorder is defined by having two of the eleven criteria listed above within a 12-month period (2-3 criteria: mild disorder; 4-5 criteria: moderate disorder; 6 or more criteria: severe disorder).