Substance dependence refers to a condition when an individual suffers from addiction to a particular substance, such as alcohol, drugs, or other addictive substances. There are several synonyms for the term substance dependence, such as chemical dependence, drug addiction, substance abuse, and substance use disorder. Chemical dependence refers to the physical and psychological reliance on a substance, while drug addiction highlights the compulsive behavior and craving for drugs or medication. Substance abuse refers to the maladaptive pattern of substance use, and substance use disorder also implies the misuse of addictive substances leading to adverse health consequences. All these terms are used interchangeably to describe the condition of addiction, and seeking help from professionals is necessary to treat substance dependence.