In A Nutshell
Many people conflate addiction and physical dependence, but they are actually quite distinct from each other. After taking a drug for a long time, someone might increase their tolerance to it and have unpleasant withdrawal symptoms if they quit using. This is physical dependence. If you are using drugs for the wrong reasons, and you allow them mess up your life but continue using them in spite of that knowledge, you are addicted.
The Whole Bushel
One of the most common and damaging mistakes is to mix up addiction with physical dependence. Addiction is more a problem with a person’s specific pattern of behavior. Conflating the two can be damaging and counterproductive. After all, you don’t want to accuse someone who is merely physically dependent on a medication of being a full-blown addict.
You see, when someone is prescribed a medication of any sort that they require over a long period of time, they may slowly build up a tolerance to it. This is similar to drinking. If you are a heavy drinker, you will likely need more and more to get to the level you want. Now imagine if you are on pills for chronic pain. Instead of tolerance meaning you don’t get as drunk as you want, it now means you aren’t handling the pain as well. If you start taking more to deal with it the cycle will only repeat itself and get worse. And with many drugs you will experience painful withdrawal symptoms upon quitting use. Likely you will need to slowly wean yourself off to avoid the worst of the withdrawal. The above is an example of physical dependence.
Addiction, on the other hand, is quite different. You might think that all addicts are physically dependent, but this is not necessarily the case either. Addiction has more to do with behavior than biological needs (though they’re obviously closely related), and addicts are characterized by their inability to keep their life together well while using their drug of choice. An addict may have poor impulse control, problems with relationships due to the drug, may steal or beg to get their fix, and will often continue using the drug no matter what the consequences may be. Of course, there are varying degrees of addiction. Not all people who are addicted will steal your electronics. It all depends on the person, the drug, and the level of addiction.