Canada

It was a strange take in the 1980s when the disease model was the best we had. Today it is well accepted that most drugs alone don't typically produce addiction. Just not by conservative voters, who still act like addiction is a moral failing, because people choose to do drugs "the first time," and then become "chemically addicted".

Please see, for example:

The concept of physical dependence implies a deterministic outlook which limits seriously any therapeutic hope. It predicts that once a user has taken a dangerous drug he or she will be hooked, with little chance to gain control. It also implies a social policy advocating total prohibition, since the drug itself is seen as the cause of addiction. The person is seen as passive and helpless in front of the pernicious substance. Alexander and Hadway [20] have called such a view the exposure orientation on addiction. They contrast it with an adaptive view of addiction which suggests that drug use is an attempt to reduce the distress that existed before it was first taken. Opiate users thus are at risk of addiction only under special circumstances, that is, when they are confronting difficult situations and trying to cope by turning to drugs. The problem lies in the persons's psychological deficiencies and not in the drug itself. Thus, drug prohibition would be of no effect since the individual would still have to confront his or her stress and deal with it. In this view, the user has the choice of finding alternatives, searching for help and ultimately abandoning his or her dangerous habit.

A number of facts show that there is no universal and exclusive connection between such drugs as opiates and physical addiction. Any person using drugs does not necessarily become an addict. The effects of psychoactive substances are extremely variable from person to person and are relative to a number of factors among which are prior history of drug use, genetic susceptibility, cognitive factors, such as expectancy and attributions, environmental stresses, personality and opportunities for exposure [22]. People who have come to use drugs by accident, such as hospital residents who were given regular doses of morphine for pain relief, have not demonstrated an irresistible craving for such substances after release. It is estimated that about one quarter of the American soldiers in Viet Nam took heroin. Most of them, once back home, were able to quit without major difficulties. Similar observations hold for the period of the American Civil War. The case of controlled users, of which physicians are the best known group, shows that regular intakes of opiates over decades do not lead to tolerance or to withdrawal symptoms during abstinence. Heroin can be used on a regular but infrequent basis without dependence or catastrophic consequence [23]. It has also been found that former heroin addicts can completely stop using it or shift to casual use. Epidemiological studies have established that many heroin users are adolescents who grow out of their addiction and become abstinent later in life. People can experience withdrawal symptoms from much milder substances than opiates, such as sedatives, tranquillizers, laxatives, nicotine and caffeine. This evidence shows that no deterministic physiological mechanism can explain physical addiction exclusively.