Final answer:
The severity and speed of opioid withdrawal depend on the drug's tolerance level. Tolerance leads to increased risk of withdrawal symptoms, and withdrawal can involve pain, flu-like symptoms, and psychological effects.
Step-by-step explanation:
The severity and speed of withdrawal associated with opioids depend on the tolerance of the opioid used. Tolerance occurs when a drug user requires more and more of a given drug to experience the same effects. As tolerance develops, the risk for withdrawal symptoms increases, requiring higher quantities of the opioid to achieve the desired effects. Opioids, such as heroin, morphine, methadone, and codeine, all have the potential to lead to addiction and present various withdrawal symptoms, which can include severe pain, flu-like symptoms, and psychological effects like anxiety and depression. The withdrawal experience can be so intense that medications such as methadone or buprenorphine may be used to alleviate these symptoms during rehabilitation.