For many people risk reduction can be complicated by other factors. Someone's social and economic situation will strongly affect their ability to take on information and change their behaviour. In some cases practical help with benefits and housing may be the most effective harm reduction strategy as this may create the setting for someone to use the information they have learned about safer drug use.

Unexpected barriers may appear which cause people to be at risk. Someone may get sterile injecting equipment but drop it when they see the police coming towards them. Also people's emotional state and mental health may affect their ability to implement harm reduction strategies. Someone who is very upset may take a risk they would otherwise avoid. Finally, if someone has consumed a large amount of drugs or alcohol this may restrict their ability to act more safely.

It is vital to acknowledge the realities of people's lives and accept that change is a process, not a one–off event. If small changes are noted they need to be positively reinforced and built upon.

Policy and practice

Since the 1960s heroin users have been offered drug treatment programmes based on heroin substitutes such as physeptone, DF118, diamorphine and, most commonly, oral methadone, and more recently lofexidine and buprenorphine. There are different views as to the role and value of drug treatment programmes. Some people believe that heroin substitutes should only be employed to support drug users to stop using heroin: an abstinence policy. Others believe that heroin substitutes can also be used to help people control their drug use through maintenance programmes: a harm reduction policy.

Since the advent of HIV infection a stronger harm reduction approach has been promoted. The Advisory Council on the Misuse of Drugs (ACMD) in their first AIDS and Drug Misuse Report (1989) argued that preventing the spread of HIV infection should take precedence over attempts to reduce drug taking, as HIV posed a greater threat to the individual and society.

The second ACMD report on AIDS and Drug Misuse (1991) stressed the role of prescribing as a harm reduction tool. This was again reinforced in the Department of Health's advice to doctors in their report: Drug Misuse and Dependence: Guidelines on Clinical Management (1991).

However, despite a shift in policy towards harm reduction over the last ten years, practice remains divided between abstinence and harm reduction policies and will vary from area to area and from project to project. On one side are those who still take an abstinence approach to prescribing, offering reduction programmes to those who wish to stop using drugs. On the other side are those offering low threshold schemes where as many users as possible are promoted to enter drug maintenance programmes to encourage them into services and away from daily injecting.

Within these two extremes can be found a whole spectrum of various practices and policies. It is important to recognise that even where very experimental harm reduction drug prescribing is offered to users, some will still wish to stop using. Prescribing is generally far more available than ten years ago and is increasingly accepted as a valuable tool in preventing the spread of HIV infection among injecting drug users and reducing other drug related harm.

Drug treatment programmes are usually undertaken by drug dependency units (DDUs), community drug teams (CDT's) or street drug agencies. DDUs will have their own medical team. CDT's and street agencies may have their own medical staff or work in conjunction with general practitioners. Some GPs may also prescribe without support from drug agencies.

Finally, some private doctors prescribe to drug users. They will usually tend to be more harm reduction orientated or liberal in their prescribing and offer options such as injectable alternatives to street heroin which are less available on the NHS.