This thesis explores the pharmacological aspects of drug addiction, focusing on six commonly abused substances: opioids, cannabinoids, ethanol, amphetamines, cocaine, and nicotine.It examines how these substances interact with the central nervous system, particularly the dopaminergic reward pathway, leading to long-term neuroadaptations and dependence.Despite differing pharmacokinetic and pharmacodynamic profiles, these drugs produce similar patterns of tolerance, withdrawal, and compulsive behavior.The thesis also evaluates current pharmacotherapies used to treat substance dependence, highlighting both their efficacy and limitations.Particular attention is given to treatment gaps, especially in stimulant and cannabinoid addiction.The findings underscore the need for integrative approaches that combine pharmacological interventions with psychosocial support.