Which substances are addictive?

Great Question: How do I answer this question and it should be answered, not for substances only. The question has in fact evoked more questions in my mind when I think I have an answer From Nicotine to Caffeine From Alcohol to Heroin and in-betweens, From Eating disorders to Runners, From gambling to Promiscuity, all can be addictive. Its the pleasurable effect altering our mental state. No good answer. .