Why do people abuse drugs?

Many reasons: The explanation that a psychiatrist gave me makes the most sense and fits with what i've seen. Recreational drug abusers are seeking friendship, an activity that brings them together, gives some pleasure, and because is it illegal creates bonds. Smoking starts smoking among friends as does unhealthy alcohol use; control can go later. Addiction to opiates is treacherous in folks with chronic pain.

Another reason: I agree with the first answer. Another reason is that people are using substances to cover up deep and unconscious negative emotions perceived as taboo (e.g. Anger, sadness, shame, fear, sexual feelings, etc).