Codeine is converted to morphine in the liver (to varying degrees in different cultural populations), so from a practical standpoint there is no difference between an addiction to nurophen
vs any other opiate, such as
oxycodone or heroin. The ibuprofen is more physically harmful than the codeine (with the exception of overdose, when codeine will kill person through respiratory depression just as will other opiates, particularly if combined with valium-type meds or alcohol).