Drug addiction. Abstract artwork of the blank face of a drug dependent person taking a capsule while trapped inside a drug prescription bottle. The bottle represents the lack of free will this person now has. Drug addiction is the compulsive desire to keep taking drugs either to produce the drug's desired effects or to prevent the ill- effects of withdrawal. Psychological dependence produces cravings, while physical dependence produces withdrawal syndrome if the drug is not taken. Tranquilizers are one of the most common causes of addiction.