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Passage：

The sociologist Lewis Yablonsky has identified five stages in the development of a drug dependency. The stages are experimentation, occasional use, regular use, problem/risky use, and dependency. Experimentation generally involves trying a drug once or a few times. Occasional use involves using the drug on weekends or at parties, but not using it during the week. Regular use involves using the drug on a daily or near-daily basis. Problem/risky use is associated with negative consequences, such as being arrested for drug possession or suffering from health problems as a result of drug use. At the dependency stage, a person feels a strong need to use the drug regularly and is unable to quit even in the face of serious consequences.
Question:
What are the five stages of drug dependency?
The five stages of drug dependency are experimentation, occasional use, regular use, problem or risky use, and dependency.