These definitions have partly been derived from World Health Organisation, United Nations, and European texts and those of the International Harm Reduction Association. They have however been adapted and supplemented to fit the UK context and the Findings indexing system. They are pragmatically intended to aid searching on this site, not to be authoritative definitions.

The topics covered on this site

Within the spectrum of evaluations on interventions you can search this site under the following broad themes. Note that only terms which may not be self-evident are explained here.

National or regional policies

Studies relevant to decisions taken at a national regional or international level and coordinated national policies on drug or alcohol problems. Also includes studies relevant to interventions intended to have effects noticeable at the level of an entire population or sub-population or studies which measure effects at these levels. Cross-population health impacts are singled out under the label Public health.


Interventions intended to prevent or delay the initiation of substance use and/or progression to more frequent, regular or harmful use. The targets are people who have not used the substance(s) concerned or not used them in these ways and may never do so. At one end are universal approaches which target whole populations. At the other are interventions focused on individuals (‘indicated’ prevention) or groups (‘selective’ prevention) identified as at high risk of initiating these forms of substance use.

Because the aim is to intercept the development of problems before they begin, typically the targets for preventive interventions are young. Young people are most easily reached en masse in schools, so this is the typical site for such interventions, and educational approaches are the typical modality. However, there is a strong argument that education should primarily be judged against educational objectives, and that it is both inappropriate and largely futile to expect behaviour change in the form of substance use prevention. That on this site education is gathered under the prevention theme is not a pronouncement on this argument one way or the other but merely reflects the fact that most studies test education against preventive objectives and most site visitors will expect to find it there.

Other preventive approaches seek to influence risk factors across a whole community (including but not limited to the schools) and/or to affect children via their parents.

Reducing harm

Interventions intended to reduce the harm resulting from substance use even if use continues and often even if it continues at the same level. The harms may be to the user or to the community and they may be medical, psychological social or economic in nature. Because these approaches presuppose that significant (ie, worth investing in an intervention to reduce it) harm is already occurring, the ultimate targets are typically people already using substances in a way which results in the harms being addressed. Typically the aim is to change the way they use those (or those types of) substances so harms are reduced.

Among the greatest harms are overdose fatalities and infectious diseases caused by viruses like HIV and hepatitis C. Common interventions include needle exchanges providing infection-free injecting equipment and educational and skills training intended to ensure that substance users avoid particularly risky practices. ‘Wet’ centres which reduce nuisance to the community and provide services for treatment-resistant alcoholics by allowing them to drink on the premises are another example.

Interventions which substitute a prescribed drug of the same type for the original (and usually illegally obtained) substance often have both harm reduction and treatment objectives and take place in a medical context. These can be accessed under the Medical treatment theme and also under this theme if they have a strong harm reduction ethos.

Harm reduction activities such as substitute prescribing and needle exchange may take place in a criminal justice context, in which case they are accessible under this theme and under the Safeguarding the community theme.

Therapeutic interventions and medical or psychosocial treatment

Treatment presupposes an individual already experiencing problems related to their substance use serious enough to cause them to seek (or be directed) to stop, reduce or substantially alter their use, who feels or is judged as in need of formal help to do so, and whose problems are also seen by the broader society and/or by the treatment provider as warranting that help. Inability to resolve problems without formal help is associated with being dependent on (or addicted to) the substance(s) concerned and lacking the psychological, social or practical resources to overcome that dependence.

Check the box Entering treatment for how people get referred to or otherwise come in contact with therapeutic services. An important element in any therapeutic intervention is the relationship between the patient and their therapist or other treatment provider; for studies relevant to this issue check the box Therapeutic relationships. Organisational factors refers to dimensions of the service such as administrative procedures, management, staff training and morale, funding, accreditation, ethos and ability or willingness to respond to individual needs. Case management is closely allied to Social reintegration because typically it entails an attempt to coordinate a range of service catering not just for substance use problems but housing, employment and mental health.

Formal interventions harness and hope to accelerate and extend the normal healing/recovery process which enables many people to recover without recourse to treatment. Because natural recovery has lessons for and is closely allied to treatment, it is also included under this heading. Often too people don’t seek help for substance use problems but are identified as at risk of or already experiencing such problems, typically by a medical professional they are seeing for another reason. This can happen as part of a formal programme of screening for risky substance use (using for example short questionnaires or biological tests) followed by typically brief advice. For these initiatives check Screening & brief intervention. For these and other interventions conducted by or set in primary care and other services not specialising in substance use, check the box Primary care/non-specialist.

Treatment focuses on the client’s or patient’s welfare and quality of life, improvements in which usually require interventions to overcome their dependence. While ethically that must be the treatment provider’s focus, their work may be organised and funded by authorities whose primary motivation is to safeguard the wider community. In these cases treatment is offered not because the substance user has sought it, but because the authorities believe the individual has substance use problems susceptible to treatments which could result in benefits to the community. Typically these individuals are offenders whose crime is thought to be driven by the need to fund dependent substance use. These interventions can be accessed both under this theme and under Working with offenders in the Crime reduction theme. You can also select any other topic and combine it with the filter term Offenders to narrow down on studies on that topic involving offenders. Some types of treatment feature strong Reducing harm objectives and/or effects or shade in to Prevention approaches which seek to prevent problems developing or becoming serious among high risk groups.

Medical treatment

Treatment conducted in a medical context, usually involving medications. The essential aim is to overcome dependence or at least overcome dependence on particularly damaging and/or illegal substances, but other ‘comorbid’ medical conditions may also treated. Often these are psychiatric in nature (perhaps part of the reason why the patient was unable to resolve their substance use problems without treatment) but they may also be physical ailments related to substance use such as infectious diseases and alcohol-related deficiencies. Withdrawal symptoms may be one of those ailments and interventions may seek to reduce these without seeking to overcome the dependence which caused them, but ideally both aims are pursued.

Substituting less harmful prescribed drugs for the drugs which caused the patient’s problems is sometimes seen primarily as a way of Reducing harm in the form of death and disease, and sometimes as a Treatment intervention aiming to improve health and quality of life by overcoming dependence on the original substances. Whatever the objective, studies of such interventions are indexed under this theme and, if harm reduction is a major and explicit objective, also under that theme.

Psychosocial therapies

Treatment modalities which may or may not take place in medical settings, but which are based on psychological principles and methods such as learning theories and theories of motivation, on the harnessing of social influences such as in group and family therapies and community living arrangements. Often also includes more practical interventions such as training, housing, vocational rehabilitation, and activities which build self-esteem, confidence and social skills and provide an alternative, dependence-free lifestyle.

These types of processes are also thought to underpin the effectiveness of mutual aid networks such as Alcoholics Anonymous. For convenience these topics are also gathered under this theme. Included here too are formal treatments based on mutual aid principles or which seek to promote involvement in mutual aid networks.

Crime reduction

Many interventions not primarily intended to reduce crime nevertheless do so because they help prevent or resolve substance use problems. Check the box Studies reporting crime as an outcome to search for these studies as well as studies of crime-reduction interventions as such. The latter may involve straightforward enforcement of laws restricting substance use, enforcement as one element within broader Community strategies which attempt to engage the community in combating substance-related crime (eg, city centre strategies to address alcohol-related violence), offering Treatment instead of or as well as penal sanctions in order to rehabilitate offenders before (Pre-conviction initiatives) or after (Working with offenders) prosecution, or implementing Reducing harm interventions in prisons in recognition of continuing substance use.

Drink driving (check box Impaired driving/work) is one of the major crimes addressed because of alcohol’s adverse effects on performance. For convenience other performance-related coercive measures such as workplace testing for substance use are gathered under the same sub-theme.

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