When does physical dependence on a drug occur?

Depending on the drug, the dose used, and a number of other factors physical dependence may not occur at all although when it does occur it typically requires at least several weeks of continuious use for physical dependence to start to set in. Continuous use of opioids, corticosteroids, beta- blockers, and alcohol nearly always lead to physical dependence sooner or later. Other drugs like benzodiazepines, contrary to popular belief, actually only cause significant physical dependence in about 1/3 of long-term users (even as long as two or more years). However people that abuse benzodiazepines and similar drugs have a greater chance of becoming physically dependent. It should also be clear that physical dependence is not that same as addiction. Many drugs including corticosteroids are not drugs of abuse yet continuous use can cause physical dependence in a matter of days when taken in moderate to large doses. Addiction is psychological dependence however many addicts addicted to drugs that tend to cause physical dependence like opioids will also be physically dependent. However most people prescribed opioids for a legitimate needed for a protracted period do not become addicted but do become physically dependent.