Most drug use starts as a recreational usage and turns into addiction over time. We think we can control it and quit anytime we want—but we can’t. Drugs change the brain’s chemistry, making it difficult to stop using on your own.
And, the more you use, the more you need to get the same high as you did when you first started. If you attempt to stop the drug usage cold, you will experience physical withdrawal symptoms. Psychological dependence occurs in the final step, when you will do anything to get high.