How come doctors can give people drugs without telling them about the physical addiction until it's a problem ?

i believe in many cases the drugs provided are meant to be short term and perhaps they feel the pros out weigh the cons, if you ever feel its becoming an issue talk to the doctor to explain its too much for you to handle, as with all counsellors and doctors etc, they can only go by the information they get told and the symptoms presented, communication is key to maintaining a safe and beneficial plan of approach.

because this would give the person placebo affects of addiction. if a Doc tor says this is physically addictive then becoause he's a doctor we'll be looking for the addicition if it's not there

It's not an addiction until you, yourself have made it one really, and that means that they cannot know for sure that this will become an addiction in any form until it has already happened.

I have been prescribed copious amounts of prescription narcotics. I was always told it could become a problem, they're addictive etc. on the other hand benzodiazepines I was never warned about, it's not just, that doctors aren't forced to explain the possible risks of medications: sometimes the medication might be exactly what someone needs, but they should still be aware of the side effects.