Obviously, this would depend on what the person preferred to be involved with.  But, when it comes to prescription medication/opioids — probably some of the more commonly abused ones would be Vicodin, for example.  Vicodin is a drug that's commonly prescribed when people get injuries and suffer from pain over a decent period. People will start to take the Vicodin medication a lot of times and become addicted.

At first, these drugs can make you feel euphoric, and in that euphoria, they also provide relief from pain. This initial appeal is significant for those who are struggling with pain and are vulnerable to opioid addiction.  Vicodin or Hydrocodone, for instance, can be abused, with individuals seeking multiple prescriptions or resorting to the black market.

Vicodin, Oxycodone, OxyContin

Another commonly abused opioid or prescription medication is Oxycodone or OxyContin.  This drug is again used for pain, and it's something that is well-known to be abused and is well-known to have addictive characteristics, it's one of the drugs that I see a lot being sold on the black market.

People will get it and sell it to other people.  They even make a business out of it.  Once you get addicted, it's very hard to become un-addicted to this particular drug.

In addition to OxyContin, I think probably the most addictive drug is heroin.  It's highly addictive, and it is highly degrading to the human body and the human spirit.  Heroin is probably one of the worst drugs that an individual could be addicted to.  It's very expensive.

You don't need as much of it to get high and to get the effect that people are looking for.  People are ingesting it in many different ways.

Methamphetamine

Another, and I think one of the more commonly addictive opioids or drugs, would be methamphetamine.  People become addicted, and it pretty much destroys their lives, their bodies, their mind, their teeth, and their health.  So, definitely, methamphetamine is a highly addictive drug that gets people in a position where they cannot get off that particular job.

So, there's a whole slew of different drugs, and I think it just depends on the person — how their body reacts to a particular opioid or drug, and that's why there are so many different things that can be used to help or cure people from drug addiction.

However, the most significant factor in the successful recovery of an addict who continues to abuse drugs is their will.  While there are numerous interventions available to help those struggling with opioid/drug abuse, the individual's desire to lead a clean and sober life is paramount.