What is Drug Dependence - Drug Dependency?

Drug dependency refers to either a psychological or physiological need for a drug. Drug dependence is a mental illness and is thought to change the brain.

While most people refer to "drug addiction" as the common substance use problem, "drug dependence" is actually a more accurate term. Drug dependence is the term used in medicine and is specifically defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM). Drug abuse, along with drug dependence, make up the category of substance use disorders.

Drug dependency encompasses physiological and psychological symptoms related to the obsessive craving and using of a drug.

Drug Dependence - What is Drug Dependency?

Drug dependence applies to any drug, including alcohol, that is consumed repeatedly in spite of the negative consequences the drug use is having on the life of the drug user and the lives of those around the user. Drug dependence indicates the drug user is dependent on the drug either physically, psychologically or both in order to function in everyday life. (read: physical and psychological effects of drug addiction)

Drug Dependence - Drug Dependency and the Brain

Drug dependence is defined in the DSM as a recognized medical illness in part because of the way drug dependency affects the brain.

While each substance is different, drugs tend to release the chemicals dopamine and serotonin in the brain. These chemicals flood parts of the brain, specifically the reward center, being perceived as extremely pleasurable. Repeatedly releasing large amounts of these chemicals results in the brain adapting to the increase in dopamine and serotonin by decreasing the number of chemical receptors. This change in chemical receptors decreases the drug user's ability to enjoy things that previously brought them pleasure. The user must take more of the drug to feel good again, creating drug dependence.1

Drug dependence is also thought to involve other parts of the brain. Stress mechanisms, neuron creation and communication, learning and memory are all thought to be part of drug dependency.

Drug Dependence - Symptoms of Drug Dependency

A drug user may be, or feel, dependent on a drug in many ways. This drug dependency is seen in the way the user compulsively and repetitively uses their substance of choice. Symptoms of drug dependency include:

  • Drug tolerance - increasing amount of the drug are needed to achieve the same high
  • Withdrawal symptoms when not using the drug
  • Severe cravings for the drug
  • Taking dangerous amounts of the drug
  • Fixation on finding ways to afford the drug, drug buying and places to use the drug
  • Needing the drug to function, for example, needing it "to get going" in the morning

article references

APA Reference
Tracy, N. (2021, December 15). What is Drug Dependence - Drug Dependency?, HealthyPlace. Retrieved on 2024, June 22 from

Last Updated: December 29, 2021

Medically reviewed by Harry Croft, MD

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