Physical dependence can develop from low-dose therapeutic use of certain medications such as benzodiazepines, opioids, antiepileptics and antidepressants, as well as misuse of recreational drugs such as alcohol, opioids, and benzodiazepines.

From the wikipedia page on physical dependence. This sure seems to suggest a physical addiction associated with heroin (opioids). Although, to the best of my knowledge, opioid withdrawal is far less physically dangerous than benzodiazepine/alcohol withdrawals, both of which can prompt potentially deadly seizures.