What Is Substance Dependence?

Substance dependence occurs when a person is physically dependent on a substance such as alcohol, nicotine, drugs, or medication, to the extent that their body adapts to it and develops a tolerance to it, resulting in withdrawal symptoms when they stop using it. It is a complex condition that affects the person’s brain, body, and behavior.

Substance dependence and substance abuse used to be classified as separate health conditions in the Diagnostic and Statistical Manual of Mental Disorders (DSM), which is the guiding manual for diagnosing mental health conditions. However, the latest edition, DSM-5, has included both conditions under the umbrella term of substance use disorder.

According to the Substance Abuse and Mental Health Services Administration (SAMHSA), approximately 20 million people in the United States over the age of 12 experienced a substance use disorder in 2019. It is estimated that substance use disorders cost the United States $420 billion dollars a year.

This article explores the symptoms, causes, stages, and treatment of substance dependence, also known as substance use disorder.

Commonly Used Substances

These are some of the most commonly used types of substances:

• Depressants, which reduce anxiety and cause drowsiness. Depressants include alcohol as well as certain types of medications such as benzodiazepines (Valium, Xanax, and Ativan), barbiturates, chloral hydrate, and paraldehyde. 
• Stimulants, which stimulate the brain and nervous system. Stimulants include drugs like cocaine and amphetamines. Amphetamines are also used in certain stimulant medications, like Ritalin, that help treat conditions like ADHD.
• Hallucinogens, which cause people to hear or see things that don’t exist. Hallucinogens include drugs such as LSD, psilocybin (commonly known as mushrooms), mescaline, and phencyclidine (known as PCP or angel dust).
• Opiates and narcotics, are strong painkillers that reduce pain, induce drowsiness, and produce feelings of well-being, happiness, and excitement. Opiates include drugs like heroin and opium, as well as pain-relieving medications, such as Vicodin and morphine.
• Marijuana, which produces a sense of happiness, calm, and relaxation.

Substance Dependence Symptoms

These are some of the symptoms and behaviors associated with substance dependence and substance use disorder:

• Needing the substance on a daily basis
• Developing a tolerance to the substance and needing to take more of it over time to achieve the same effect
• Losing control over use of the substance and being unable to stop using it
• Experiencing withdrawal symptoms upon stopping one’s use of the substance
• Spending a lot of time procuring, using, and recovering from the aftereffects of the substance
• Using the substance in risky settings
• Missing school or work, or performing poorly
• Avoiding recreational and social activities due to substance use
• Continuing to use the substance despite negative consequences to one’s family, work, and health
• Making excuses to use the substance
• Using the substance when alone 
• Resorting to secretive behaviors to hide one’s use of the substance
• Becoming hostile when confronted with one’s substance dependence
• Neglecting to eat and maintain personal hygiene

Stages of Substance Use 

Substance use often progresses in stages, which can include:

1. Experimentation: This stage often involves trying different substances with one’s peers, sometimes with the goal of defying one’s parents or other authority figures.
2. Regular use: This stage involves using the substance more often, displaying an increased ability to handle it, and starting to develop a tolerance to it. The person may use the substance to try and fix negative feelings. Their loved ones may notice that they are starting to miss school or work, and that they spend less time with their family and friends and more time with people who are misusing drugs as well.
3. Dependence: Dependence occurs when the person’s body adapts to the substance and becomes physically dependent on it, causing them to need more and more of it to achieve the same effect.
4. Problematic use: The person prioritizes their use of the substance over everything else, including their relationships, school, work, family, and other interests. They lose all motivation to do anything else and display significant behavior changes. They may worry about losing their source of the substance, engage in risky or secretive behaviors to obtain more of it or even start selling it themselves, to support their habit.
5. Addiction: In this stage, the person loses control over their use of the substance and cannot face everyday life without it. They deny that they have a problem despite mounting health issues, family conflicts, financial difficulties, and legal problems as a result of their substance use. 

Causes of Substance Dependence

According to the American Psychiatric Association (APA), addictive substances like alcohol and drugs cause changes in the brain that trigger intense cravings for the substance.

However, the APA explains that as the brain and body adapt to the effects of the substance, the person needs to consume more and more of it to achieve the same effect. This leads to a cycle of addiction and dependence that contributes to substance use disorder.

A combination of factors can contribute to the risk of developing substance use disorder, including:

• Social pressures
• Environmental stressors 
• Genetic vulnerability
• Individual personality characteristics
• Mental health conditions

Diagnosing Substance Dependence

If you suspect you may have become physically dependent on a prescription medication that your healthcare provider has asked you to take, contact the physician who prescribed the medication to you. 

On the other hand, if you think you have become dependent on a substance such as alcohol, drugs, nicotine, or prescription medication that you’re not supposed to be taking, contact a healthcare provider such as your family doctor or primary care physician. They can diagnose your condition or refer you to a healthcare provider who can.

Your healthcare provider will determine whether your symptoms match the criteria for substance use disorder listed in the DSM-5. Depending on how many symptoms you have, your condition may be classified as mild, moderate, or severe.

Substance Dependence Treatment

Treatment for substance dependence can vary depending on factors such as:

• Age
• Medical history
• Symptom severity
• Dependence severity
• Type of substance used
• Tolerance for medication, procedures, and other treatments
• Lifestyle and personal preference

A Word From Verywell

Substance dependence and addiction are complex conditions; however, they are treatable. If you or a loved one are experiencing dependence, it’s important to seek help and treatment as soon as possible.