What is the Difference Between a Physical vs Psychological Dependency

Some people use the terms “dependent” and “addicted” interchangeably to describe someone who cannot stop using a substance or repeating a behavior. On the contrary, these are two very different terms.
“Addiction”, or psychological dependency, is a term used to describe someone who is mentally dependent on a substance or action. They use the action or substance to get high rather than to treat a condition. Psychological dependency can be detrimental by causing the addicted person to neglect responsibilities or personal relationships in lieu of obtaining more of the drug.
Physical dependence is not necessarily negative. People can be physically dependent on substances such as insulin or pain medication in order to function normally. Physical dependence is a bodily reaction that occurs with prolonged use of substances that can include prescription drugs, illegal drugs, and alcohol.
Physical dependence is defined by the presence of withdrawal symptoms. Substances react with the brain to produce certain chemicals that make the individual feel happy, energetic, or productive. The brain produces these chemicals naturally in smaller amounts and releases them when good things happen, like winning a game, getting a promotion, etc. When people take a substance often enough, the brain stops producing as much of these chemicals naturally and becomes dependent on the drug for the chemicals. If the person then stops taking the drug, withdrawal sets in. Withdrawal symptoms for most drugs and some behaviors can be compared to a severe case of the flu: anxiety, tremors, hot and cold flashes, aches, loss of appetite, fever, nausea, insomnia, vomiting, etc. This acts as negative reinforcement, motivating continued use of the drug or behavior.
Behaviors are generally psychologically addicting, and it is very rare for someone to experience physical withdrawal symptoms from a behavior, however, a lot of the emotional symptoms – irritability, anger, etc. – can be seen when an individual stops a physical behavior to which they were dependent. Exercise addiction, however, can produce physical withdrawal symptoms because exercise causes the brain to release feel-good chemicals called endorphins. Behaviors such as gambling, sex, shopping, and even internet use can be psychologically addicting enough to cause the individual problems in their personal, financial, or professional lives.
Because physical dependence can occur with or without psychological addiction, the main functional difference between the two is that addiction means that important social, occupational, or recreational activities are given up or reduced because of substance use. Physical dependence typically occurs in people using pain medications, even if they have a prescription. If the person has pain that occurs all the time, such as a back injury, they will need to take pain medication all the time to treat the pain. Over time, the body becomes tolerant to the medication and the person has to increase their dose to achieve the same pain management effect. This should only be done with the supervision of a doctor, and as long as the person follows a controlled regimen and doesn’t experience negative consequences due to their drug use, they are not psychologically dependent.