P 1 2 3 4 5 6 7 8 9 10 11 12 Week of treatment PFeigrcuernet 3days abstinent during treatment Percent days abstinent during treatment. Percent days absti- nent at pre-treatment and during the 12 weeks of treatment for patients who received 0, 1 or 12 treatment sessions. The effective improvement in drinking was instantaneous, evident at week 1. The improvement was maintained at the same approximate level for the 12 weeks of scheduled treatment. The effect occurred for all groups, whether they attended all 12 treatment sessions, only one treatment session, or did not attend any treatment sessions. See also Figure 4. P 1 2 3 4 5 6 7 8 9 10 11 12 Week of treatment FDirginukrsep4er drinking day during treatment Drinks per drinking day during treatment. Drinks per drink- ing day at pre-treatment and during the 12 weeks of treat- ment for patients who received 0, 1 or 12 treatment sessions. The effective improvement in drinking was instanta- neous, evident at week 1. The improvement was maintained at the same approximate level for the 12 weeks of scheduled treatment. The effect occurred for all groups, whether they attended all 12 treatment sessions, only one treatment ses- sion, or did not attend any treatment sessions. See also Fig- ure 3. BMC Public Health 2005, 5:75 http://www.biomedcentral.com/1471-2458/5/75 tn100% e n its 80% b a 60% s y ad 40% t en 20% c r e 0% P y ad25 g in20 k n ir 15 d r e10 p s k 5 n i r D 0 12 0 1 1 0 12 Nearly two thirds of the long term improvement in the full treatment group was matched by the untreated rapid dropout group (Figures 1 &2 and Table 6). Only in the remaining one third could there be a subcomponent con- sisting of a treatment effect. Most of the improvement was instantaneous, occurring at week 1, before the participants had received the bulk of their treatment (Figures 3 &4 and Table 6). Although the full treatment group received 11 more therapy sessions, the additional improvement was of small magnitude. For example, at week one percent days abstinence had increased by over 60%, and the additional 11 weeks of treatment increased it by only 4%. If treatment were the causal agent we would expect that the effect would occur over the course of weeks with the administration of treatment. There was a similar instantaneous improvement in untreated alcoholics (Figures 3 &4 and Table 6). The effect size estimates suggested that nearly three fourths of the instantaneous improvement in the full treatment group was matched by the untreated group. Those who received zero treatment sessions had better outcomes than those who received one session (Figures 1 to 4 and Tables 4 to 6). The implication of this is discussed below. Improvement was maintained over time even in the no treatment group (Figures 1 to 4 and Table 6). Change from week 1 to follow-up was not significantly different between the zero and full treatment groups. In both groups the week 1 to week 12 improvement was lost by follow-up. These data do not support the contention that retention of clients in treatment for as long as possible increases the chances that they will derive benefit from therapy. A more reasonable interpretation of these data is that they illustrate the importance of selection effects, i.e., partici- pants who reduce their alcohol consumption are more likely to enter or remain in treatment and those who continue drinking are more likely to drop out of treat- ment. One of the best studies of alcoholism treatment outcome was conducted by the Rand Corporation in the late 1970s [10]. Participants were patients who attended inpatient or outpatient treatment at centers across the United States. They found that "it is possible that the cor- relation [between attendance and outcome] arises from selection effects, such that the better motivated or more successful patients continue in treatment, whereas the more intractable cases drop out. Such a pattern could result from subject self-selection or from the operation of the treatment environment in encouraging continued Page 8 of 11 (page number not for citation purposes)