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Research analysis

This entry is our analysis of a study added to the Effectiveness Bank. The original study was not published by Findings; click Title to order a copy. Free reprints may be available from the authors – click prepared e-mail. Links to other documents. Hover over for notes. Click to highlight passage referred to. Unfold extra text Unfold supplementary text The Summary conveys the findings and views expressed in the study. Below is a commentary from Drug and Alcohol Findings.

Title and link for copying Comment/query to editor

Randomized controlled trial of a cognitive-behavioral motivational intervention in a group versus individual format for substance use disorders.

Sobell L.C., Sobell M.B., Agrawal S.
Psychology of Addictive Behaviors: 2009, 23(4), p. 672–683.
Unable to obtain a copy by clicking title? Try asking the author for a reprint by adapting this prepared e-mail or by writing to Dr Sobell at You could also try this alternative source.

For US problem drinkers and drug users not at the severest end of the spectrum, four sessions of group were as effective as four of individual therapy but took much fewer therapist hours per patient. The little research we have suggests this a common finding, commending group approaches on cost-effectiveness grounds.

Summary Despite the popularity of group-based therapies for substance use problems, just four studies have directly compared outcomes from the same treatment delivered in a group versus an individual format. Each found substance use reductions which did not significantly differ between the formats.

The featured study aimed to add to this scarce literature by randomising problem drinkers and drug users who were not severely dependent to group versus individual formats of the Guided Self-Change Treatment Model. The approach combines motivational interviewing style and techniques with cognitive-behavioural elements, and was developed as a brief treatment for low severity alcohol problems. It features personalised feedback of assessment findings to clients (eg, extent of use, health risks), decisional balance exercises weighing the pros and cons of change, and advice for clients on selecting their treatment goal.

Patients were referred to a Guided Self-Change clinic in Toronto, Canada, or self-referred after seeing an advert aimed at people "Concerned about your drinking (drug use)". Very heavy or highly dependent drinkers or drug users, injectors, and primary heroin users were screened out of the study. The 231 problem drinkers and 56 problem drug (mainly cocaine or cannabis) users who qualified for and agreed to join the study were allocated as appropriate to alcohol or drug versions of the intervention, and then randomly to group Closed groups of four to eight clients with two therapists who promoted and used group processes (eg, therapists facilitated social interactions and encouraged group members to share their experiences and provide feedback to other members) throughout all sessions. or individual formats run by the same therapists. Group and individual formats were intended to run over four sessions of one and a half to two hours and one hour respectively.

264 clients attended at least the first treatment session, forming the cohort whose outcomes were analysed by the study. Of these, all but 23 completed follow-up assessments 12 months after treatment ended. The 264 patients were typically employed men in their thirties and forties and most had never before been in substance use treatment.

Main findings

Around 80% of patients completed all four sessions in both group and individual formats. Most drinkers and cannabis users opted to moderate their consumption, most cocaine users to abstain.

As a whole, while in treatment patients treated for drinking problems significantly reduced their drinking on various measures and then further in the following 12 months. For example, in the 12 months before treatment they were drinking on around 7 in 10 days and on each of these days consumed about 89g of alcohol or 11 UK units. In the 12 months after treatment the corresponding figures were 4 to 5 days and 59g. From before treatment abstaining from their main drug 39% of days, following treatment the drug users abstained on 70% of days. Both drinkers and drug users also experienced fewer adverse consequences related to their substance use.

On none of these measures did individual and group therapy differ significantly or to any appreciable degree, and nor did they differ in terms of the patients' own assessments of the degree to which their problems had improved. Purely in terms of therapist hours per patient per session, group therapy demanded 59% of the time demanded by individual therapy so on this measure was more cost-effective.

Assessed for treatment completers after treatment ended, levels of client satisfaction with both group and individual formats were high but in some respects slightly and significantly higher for one rather than the other. Asked 12 months later which format they would have preferred, most (59%) of those who had experienced group therapy would have preferred individual attention, while few (6%) who had received this would have preferred group therapy.

The authors' conclusions

The featured study found comparable outcomes for alcohol and drug users who received the same Guided Self-Change treatment delivered in a group versus individual format. Both sets of clients reported significant improvements during treatment which were sustained to the 12-month follow-up. Group treatment, however, required 41% less therapist time for the same number of clients. When the cost of rescheduling appointments is considered, the benefits of groups become even more important (ie, groups are held even if clients miss a session). In this study retention in group therapy was about as high as in individual, perhaps aided by reminder telephone calls before sessions and information handouts on the benefits of group therapy. Because health care costs continue to increase, further development and evaluations of group therapy are warranted.

Findings logo commentary With equivalent outcomes, economy seems the key advantage of the group format. The risk is that bringing heavy and/or risky substance users together will create social justifications and pressures for continued heavy use and make this seem more, not less 'normal'. But when the participants have a joint reason to collaborate in curbing their substance use – typically when they have voluntarily entered treatment with this objective in mind – in studies which directly compared them, group psychosocial therapies (and cognitive-behavioural therapy in particular) have been found equivalent to individual approaches in retention and substance use outcomes. However, such studies are usually limited to comparing outcomes among clients prepared to be randomised to either treatment. Those with strong preferences or practical reasons for choosing one of the formats have been excluded or excluded themselves.

The first two authors have produced a book on the approach tested in the featured study offering clinicians resources, a detailed intervention framework and strategies for helping clients set and meet their own treatment goals.

Thanks for their comments on this entry in draft to Linda Carter Sobell of the Nova Southeastern University in Ft. Lauderdale in the USA. Commentators bear no responsibility for the text including the interpretations and any remaining errors.

Last revised 22 January 2012

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