What Is the Difference Between Psychological and Physiological Dependence?

How do you know if you’re psychologically addicted to something or physically addicted to something? In this article, the differences between psychological and physiological dependence on drugs and other addictive substances and behaviors are explored, including a list of the ten most addictive substances, alongside best practices around treatment for addiction.

What is addiction?

Addiction is a complex and chronic brain disease characterized by compulsive drug seeking and use despite harmful consequences.

Addiction is considered a brain disease because drugs and other addictive substances can change the structure and function of the brain, leading to long-lasting changes in behavior, decision-making, and self-control.

Addiction can also result from repetitive behaviors, such as gambling or compulsive eating.

A combination of genetic, environmental, and personal factors influences the development of addiction.

Addiction is a treatable condition, but recovery often requires ongoing support and management.

How does addiction affect the brain and behavior?

Addiction affects both brain circuitry and behavior, resulting in an individual’s inability to regulate drug consumption.

The pleasurable effects of addictive substances target the brain’s reward center, creating a rapid pathway to reward that can modify an individual’s cognitive processing over time.

The propensity of drugs to be addictive can be intensified by the positive feelings they elicit during use and the negative sensations that may arise when their effects wear off.

With sustained drug abuse, individuals can develop drug dependence, leading to withdrawal symptoms and intense drug cravings in the absence of the substance.

It is important to remember that addiction can occur from a range of different substances. While conversations around addiction often refer to recreational drug misuse, many more people struggle to manage their relationship with prescription medication.

For many who live with chronic conditions, pain relief is essential and typically relies on the therapeutic use of certain medications. Dependence and addiction are issues suffered by this population as well.

What is physiological dependence?

Physiological dependence is a condition that arises from prolonged use of certain drugs. Stopping this drug use – either abruptly or gradually – leads to unpleasant physical symptoms.

The severity of physical dependence and withdrawal symptoms is influenced by the duration and dose of drug use, as well as the age of the user. Withdrawal symptoms can last for varying lengths, from days to months.

A condition known as protracted withdrawal syndrome can occur, in which low-grade symptoms continue for an extended period, potentially leading to relapse and prolonged disability. Benzodiazepines often cause this syndrome.

Physical dependence should not be equated with addiction, which is a more complex psychological problem. Physical dependence is sometimes compared to dependence on insulin for individuals with diabetes.

What is psychological dependence?

Psychological dependence is a type of mental illness where a person experiences negative feelings like anxiety and sadness when they stop using drugs or doing certain activities that they’ve been doing for a long time.

Psychological dependence happens because of how much the brain has gotten used to the drug or activity and has changed in a way that makes it hard to stop. This can happen with things like drugs but also with specific behaviors such as the use of pornography.

Which substances are most likely to cause dependence?

A 2007 study^[1] evaluated 20 substances to measure their potential harm. The study was grouped into three categories: Physical harm, Dependency, and social harm.

Results from the Dependence category were then further divided into three factors:

1. Intensity of pleasure: Drugs that induce high levels of pleasure are frequently misused due to the initial effects and subsequent euphoria
2. Psychological dependence: Psychological dependence is characterized by repeated drug use, apprehension about discontinuing use, and negative consequence
3. Physical dependence: Physical dependence involves an increasing tolerance to the drug, cravings, and withdrawal symptoms

Based on this research, here are the top 10 most addictive substances in the world, in order:

1. Heroin

Heroin is an opioid drug made from morphine. Its mean score for dependence was the highest and the highest in the other two categories.

Heroin users feel a rush of euphoria after injecting, snorting, or smoking the drug. It doesn’t take long to develop a tolerance to heroin, and users need to keep increasing their dose to get the same effect.

Unpleasant withdrawal symptoms motivate users to continue using the drug. Common signs of withdrawal are severe muscle and bone pain, diarrhea and vomiting, restlessness, cold flashes, and uncontrollable leg movements.

Long-term effects of opioid addiction can result in loss of white matter in the brain, which affects decision-making and behavior control.

2. Cocaine

Cocaine’s score was the second highest. The white powdery drug is typically inhaled through the nose and is a stimulant made from the coca plant leaves.

Drug dealers often mix it with other substances, such as cornstarch, talcum powder, or flour, to increase profits. It is also prevalent for dealers to cut cocaine with other drugs, such as fentanyl, significantly increasing the risk of overdose.

Cocaine increases dopamine levels in the brain, and frequent use stops regular communication between nerve cells. That means your brain becomes less sensitive to dopamine, and users must increase the amount they use to feel happy.

Common withdrawal symptoms are depression, nightmares and insomnia, fatigue, and slowed thinking.

Users who snort cocaine may experience loss of smell, nosebleeds, runny nose, and problems swallowing. Those who ingest the drug can have severe bowel decay.

3. Tobacco

The addictive nature of tobacco is one of the reasons it is so widely used around the world, as well as its status as both legal and common. The nicotine contained in tobacco leaves is the addictive substance in cigarettes, pipes, cigars, ‘dip,’ and vapes.

Withdrawal symptoms start with a powerful craving for tobacco, followed by irritability, trouble sleeping, issues paying attention, and an increased appetite.

Recent studies (2020) report that 30.8 million adults smoke cigarettes in the United States. The states with the most smokers are West Virginia, Kentucky, and Louisiana. The states with the least cigarette smokers are Utah and California.

4. Street methadone

Although methadone is intended to help heroin and narcotic painkiller addicts control cravings, it is still often abused.

The study had a low pleasure score on the factors for dependence but ranked high in psychological and physical dependence with a mean score of 2.08.

Methadone is available as a tablet, oral solution, or injectable liquid. According to the Department of Justice, some street names are Amidone, Chocolate Chip Cookies, Fizzies, Maria, Pastora, Salvia, and Wafer.

Withdrawal symptoms include anxiety, muscle tremors, nausea, diarrhea, vomiting, and abdominal cramps.

5. Barbiturates

Barbiturates are depressants with a mean score of 2.01 for dependence. They produce a broad spectrum of central nervous system depression ranging from mild sedation to coma.

Barbiturates come in pill form but are also abused by injecting a liquid form into the user’s body. There are many types, but some common generic names are Amobarbital, Pentobarbital, Phenobarbital, Secobarbital, and Tuinal.

Barbiturates cause mild euphoria, lack of inhibition, anxiety relief, and sleepiness.

Withdrawal symptoms can start on the second day after discontinued use and include seizures, dizziness, anxiety, insomnia, and psychosis.

6. Alcohol

Alcohol is the most widely used psychoactive drug in America. Over 86% of adults have consumed alcohol, and there are currently over 14 million adults with an alcohol use disorder.

Alcohol comes in sixth on the list of the ten most addictive substances, with a score of 1.93. It ranked high in the pleasure category, and it makes sense that most people consume alcohol to relax or celebrate.

However, excessive drinking has a long list of associated health issues, including high blood pressure, alcohol poisoning, stroke, memory problems, depression, and anxiety.

Withdrawal from alcohol can cause delirium tremens, which can result in death. Other unpleasant symptoms include tremors, hallucinations, and seizures.

7. Benzodiazepines

Benzodiazepines (‘Benzos’) are some of the most commonly prescribed medications in the US and help reduce anxiety and seizures, relax muscles, and allow users to sleep.

They are also commonly abused because of their addictive properties and have a 1.83 dependence score. Examples of Benzos include Xanax, Valium, and Restoril.

Within one to four days of discontinued use of Benzos, users may start experiencing insomnia and anxiety. After that, for the next 10 to 14 days without the drug, people might experience panic attacks, sleep disturbance, dry retching and nausea, headaches, and muscular pain and stiffness, among a host of other unpleasant symptoms.

Benzo withdrawal can be fatal in certain circumstances, meaning medically supervised detox is necessary.

8. Amphetamine

Used to treat Attention Deficit Hyperactivity Disorder (ADHD) and narcolepsy, amphetamines are stimulant drugs with a mean score of 1.67 and come eighth on the list of most addictive substances.

Illegally produced amphetamines, such as meth, are sometimes mixed with caffeine, sugar, and a binding agent. They can then be swallowed, smoked, snorted, or injected.

Soon after consuming the drug, users may feel energetic, confident, happy, and have an increased sex drive. However, it also increases heart rate and causes dry mouth and teeth grinding.

Withdrawal symptoms usually disappear after a month of not taking any drugs. They include nightmares, restlessness, aches and pains, exhaustion, depression, paranoia, confusion, and irritability.

9. Buprenorphine

While the opioid epidemic rages on, researchers are trying to counter opioid addictions with medications like buprenorphine. It is intended to suppress the symptoms of opioid withdrawal, decrease cravings for opioids, and block the effects of other opioids.

However, it still offers a euphoric and sedated feeling for users, especially ones who do not have an opioid addiction. Because of its similarities to opioids, buprenorphine has a mean score of 1.64.

10. Cannabis

The final substance on the list of the ten most addictive substances is one that most people are familiar with. Cannabis refers to all products derived from the Cannabis sativa and Cannabis indica plants, more commonly known as marijuana.

Medicinal marijuana can offer pain relief for those with chronic pain, nerve pain, or multiple sclerosis. Harvard Health says it also lessens tremors in Parkinson’s disease and can treat glaucoma.

Its dependence score is 1.51, and 30% of marijuana users show signs of a marijuana use disorder, which is associated with dependence.

Withdrawal symptoms may appear, including physical discomfort, decreased appetite, mood and sleep difficulties, cravings, and restlessness.

People who start using marijuana before 18 are up to seven times more likely to develop a marijuana use disorder.

How widespread is drug use, and what is the effect of addiction in the broader society?

According to the National Survey on Drug Use and Health (NSUDH), among people aged 12 or older in 2020, 58.7 percent (or 162.5 million people) used tobacco, alcohol, or an illicit drug in the past month.

This breaks down to 50 percent (or 138.5 million people) who drank alcohol, 18.7 percent (or 51.7 million people) who used a tobacco product, and 13.5 percent (or 37.3 million people) who used an illicit drug.

The National Institute on Drug Abuse (NIDA) reports that substance abuse and addiction result in a financial burden of more than $600 billion annually for American society, which includes healthcare expenses, legal and criminal justice costs, and decreased workplace productivity.

Treatment for addiction

Addiction is often misunderstood by many people who may wrongly assume individuals who use drugs lack moral principles or willpower and that they could quit drug use if they simply chose to.

However, drug addiction is a complex disease that typically requires more than good intentions or willpower to overcome. Drugs alter the brain in significant ways that make quitting challenging, even for those who have a strong desire to stop.

Researchers have discovered effective treatments that can aid people in their recovery from drug addiction and enable them to lead productive lives.

At The Center • A Place of HOPE, we treat chemical and prescription drug addiction, behavioral, internet, and sexual addiction.

For over 30 years, the Whole Person approach to care – founded here at The Center – has proven highly effective at treating addiction.

1. David Nutt, Leslie A King, William Saulsbury, Colin Blakemore, Development of a rational scale to assess the harm of drugs of potential misuse, The Lancet, Volume 369, Issue 9566, 2007, Pages 1047-1053,