Mediators and Moderators of Treatment Effectiveness

The investigation of mediators and moderators helps to answer questions about how and why treatment works (mediating effects) and for whom certain treatments work best (moderators). The search for mediators and moderators of treatment effects has taken place within the clinical technology model of treatment efficacy and treatment matching, which postulates that patient attri­butes and treatment process elements, respectively, con­stitute mediators and moderators of change in drinking following treatment.

Studies show that matching to therapeutic orientation is not an essential ingredient to substantially enhanced outcomes, as previously believed (Babor and Del Boca, 2003). They also indicate that the mediational mechanisms underlying several of the most popular therapies are different than what is suggested by their proponents. In general, the Technology Model of (psychotherapy) treatment effectiveness may be flawed as it applies to alcohol dependence. Instead of distinct, non­overlapping elements, therapy may work through common mechanisms, such as empathy, an effective therapist-client alliance, a desire to change, inner resources, a suppor­tive social network, and the provision of a culturally appropriate solution to a socially defined problem.

Aggregate Effects of Treatment. Given the scarcity of specialized treatment services in most countries, they are not likely to have an impact on aggregate rates of morbidity and mortality at the popu­lation level. Nevertheless, there is some evidence that treatment has the potential to produce an aggregate impact in countries where the treatment system is rela­tively well developed. For example, researchers have found an association between declining liver cirrhosis rates and the growth of specialized treatment (Smart and Mann, 2000).

Despite evidence of the effectiveness of treatment interventions, little attention has been paid to the mech­anisms of action that would translate individual benefits to the population. Treatment interventions are primarily designed to serve the needs of individual patients and clients, but there are a number of ways that these interven­tions may have an impact at community and population levels: By raising public awareness of alcohol problems, influencing national and community agendas, involving health professionals in advocacy for prevention, and providing secondary benefits to families, employers, and automobile drivers.

The effect of treatment interventions can also be manifested more directly by not only reducing the amount of alcohol consumed by the drinker (and his or her associated risks), but also influencing the social milieu of the drinker. By removing a source of reciprocal influence that is likely to contribute to the maintenance of heavy drinking subcultures, treatment may diminish the alcohol- related problem rates of an entire society.

Conclusion. This article has described a public health approach to the provision of services for people with alcohol use disorders. Such an approach is broadly conceived to include the consideration not only of specialized services for alcohol dependence, but also of medical care and social welfare services that interact with and complement specialized alcohol services. During the past 30 years, significant progress has been made in the scientific study of alcohol dependence and its treatment.

On the basis of evidence reviewed in this article, a number of conclusions appear warranted at this time:
1. People with alcohol-related problems are hetero­geneous with respect to demographic features (e.g., age, gender, race/ethnicity), age of onset of heavy drinking, severity of alcohol dependence, comorbid psychopathology, genetic vulnerability, and other pro­gnostic factors.

2. Any treatment for alcohol dependence is better than no treatment. The majority of those treated demon­strate improvement, but many improve with minimal treatment.

3. The intensity of treatment has not been shown to produce pronounced differences in outcome. Similarly, medical inpatient treatment, while more costly, is not demonstrably more effective than nonmedical residen­tial or outpatient treatment. For patients with serious comorbid medical and psychiatric disorders, medical inpatient treatment may, nonetheless, be necessary. Continuing aftercare helps to maintain abstinence fol­lowing short-term intensive rehabilitation in inpatient settings.

4. There is little evidence that any one treatment ap­proach is superior. There is some support for certain kinds of behavior therapy, but the effectiveness of AA and disulfiram seem to depend on patient character­istics and compliance. Several new pharmacological interventions show promise as a basis for a new gener­ation of ambulatory treatments, but they add little to the effect of nonpharmacological treatment.

5. Brief interventions for harmful drinkers are effective in reducing hazardous drinking and are feasible to imple­ment in primary care settings.

6. A combination of early intervention, specialized treatment, and mutual help groups has the potential to reduce the rate of alcohol-related problems in a society.

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