Call them extremists. Emotional state is another factor that can affect drug use. If someone is depressed or angry they may turn to drugs to get through the rough times and then have trouble living life without them. Even if you don't get physically addicted, you can still get mentally hooked. Abuse over time leads to tolerance, which brings on dependence.
Physical dependence is bad.
That's where you have to use the drug just to feel normal for a few minutes. Psychological dependence occurs when you continue to use despite attempts to quit, even when the drug use causes problems in your social life or career.