Psychological dependence, physical dependence and addiction are three separate but potentially overlapping problems that can affect a person who consumes street drugs, mind-altering medications and\/or alcohol. Each of these problems has a distinct impact on your health and well-being. Let\u2019s take a look at how they affect you when they appear separately or together. Psychological Dependence In essence, psychological dependence is a form of psychological addiction. An affected person may or may not have a physical dependence on drugs or alcohol, or develop an addict\u2019s characteristic uncontrolled substance intake. However, regardless of the presence\/absence of physical dependence or addiction, the individual makes substance use a primary theme of day-to-day thinking, emotional responses and actions. As a rule, if you\u2019re psychologically dependent on a substance, you have a compelling urge to consume it, even though you know it can cause serious harm. Even substances not capable of triggering physical dependence or addiction can trigger psychological dependence. Physical Dependence Physical dependence occurs when your brain comes to rely on the presence of a certain amount of an illegal drug, a medication or alcohol. Once this change occurs inside your brain, you will develop an unpleasant and potentially dangerous grouping of symptoms \u2014 known collectively as withdrawal \u2014 if you stop taking the substance in question or quickly decrease the amount you normally consume. You will also typically develop rising tolerance to the substance, which means that you\u2019ll have to take more of it to produce the accustomed effects. While many people think that physical dependence and addiction always go together, addiction specialists clearly note that you can develop physical dependence without developing an addiction. The classic example of this situation is a person with a long-term prescription for an opioid painkiller who diligently follows all of their doctor\u2019s guidelines. This person would likely go into withdrawal if intake of that medication stopped, but nevertheless does not develop out-of-control drug cravings or take excessive amounts of the painkiller. Addiction A person with a drug or alcohol addiction develops a driving urge to use the substance in question, and in turn loses control over substance intake and prioritizes that intake over other life activities. Since people affected by addiction put drug or alcohol use first, failing to meet important obligations at home, work, school and in their relationships. They also continue substance use despite being aware of the harmful impact on themselves and other people. In addition to changing your normal brain chemistry, most addictive substances produce psychological addiction and physical dependence. However, you can also develop an addiction without developing significant physical dependence. The symptoms of addiction frequently overlap with the symptoms of non-addicted substance abuse. Sources: National Institute on Drug Abuse: DrugFacts \u2013 Understanding Drug Use and Addiction Australian Government Department of Health: Physical and Psychological Dependence National Institute on Drug Abuse: Is There a Difference Between Physical Dependence and Addiction?