A Meta-Analysis of Research on Motivational Interviewing Treatment Effectiveness (MARMITE)

2. A Meta-Analysis of Research on Motivational Interviewing Treatment Effectiveness (MARMITE) Jennifer Hettema Julie Steele William R. Miller Annual Review of Clinical Psychology Vol 1, 2005 (in press)

3. funded by a grant from The Robert Wood Johnson Foundation

4. Adoption Curve for Innovations Source: Everett M. Rogers Diffusion of Innovations

5. Number of MI Publications Source: www.motivationalinterview.org/library/biblio.html MARMITE

6. MI Outcome Trials Source: www.motivationalinterview.org/library/biblio.html MARMITE

7. Inclusion Criteria for MI Trials For within-group effect sizes: • At least one treatment group including MI • At least one post-treatment outcome measure For between-group effect sizes: • At least one control or comparison condition without MI components • Procedure for creating pre-treatment equivalence of groups MARMITE

8. All studies double-coded for: • Methodological quality on 12 dimensions • Other study characteristics • Attributes of the MI intervention(s) • Within-group effect sizes • Between-group effect sizes MARMITE

9. Effect sizes were computed: • For all reported outcome variables • At all reported follow-up points • For all between-group contrasts • With 95% confidence intervals • Correcting for small sample bias MARMITE

10. 72 studies included so far: • Alcohol (31) One study each: • Drug Abuse (14) Gambling • Smoking (6) Eating Disorders • HIV Risk (5) Relationships • Treatment Compliance (5) • Water purification (4) • Diet and exercise (4) MARMITE

11. Types of Comparisons • MI vs. Specified Treatment (25) • MI vs. Treatment as Usual (6) • MI vs No Treatment / Placebo (21) • MI added to Specified Treatment (7) • MI added to Treatment as Usual (5) • Mixed Designs (6) • Within-Group Only (2) MARMITE

12. Methodological Quality Compared to 361 alcohol treatment trials: • MQS Mean = 10.76 vs. 10.68 (ns) • Intervention quality control 78% vs 57% • Multisite trials: 28% vs. 5% • Follow-up > 12 months 18% vs. 51% • Follow-up completion > 70% 45% vs. 75% MARMITE

13. Outcome (Dependent) Measures • Mean of 3.3 outcome variables per study • Range: 1 to 12 • To avoid capitalization on change, we computed a combined effect size (d) averaging across all reported outcome variables in each study MARMITE

14. Being collaborative Client centered Nonjudgmental Building trust Reducing resistance Increasing readiness Increasing self-efficacy Reflective listening Increasing discrepancy Eliciting change talk Exploring ambivalence Expressing empathy Specified Characteristics of MI MARMITE

15. Specified Characteristics of MI Of 12 possible characteristics of MI, The average number mentioned was 3.6 Range: 0-12 MARMITE

16. Treatment “Dose” of MI Average “dose” of 2 sessions (2.2 hours) The contrasts in dose varied from: Comparison group 25 hours longer than MI to MI 6 hours longer than no-treatment MARMITE

17. Quality Control of MI • Average training time: 10 hours (N=13) • Manual-guided 74% • Post-training supervision 29% • Fidelity checks 36% MARMITE

18. Outpatient clinics (15) Inpatient facilities (11) Educational settings (6) Community organizations (5) G.P. offices (5) Prenatal clinics (3) Emergency rooms (2) Halfway house (2) EAP Telephone (3) In home (1) Jail (1) Mixed (7) Unspecified (8) Where was MI tested? MARMITE

19. Who delivered MI? • Paraprofessionals / students (8) • Master’s level (6) • Psychologists (6) • Nurses (3) • Physicians (2) • Dietician (1) • Mixed (22) MARMITE

20. Sample Characteristics (N = 14,267) • N = 21 to 952 Mean = 198 • Males = 54.8% Range = 0 to 100% • Mean Age = 34 Range = 16 to 62 • Ethnic minorities: 43% (N = 37) MARMITE

21. Some Generalizations • Wide variability in effect size across studies, within problem areas (e.g., for alcohol problems, d varies from 0 to 3.0) • Effects of MI appear early • Effects of MI diminish over time, except in additive studies • d = .77 at post-treatment • d = .31 at 4-6 months • d = .30 at 6-12 months MARMITE

22. Effect Size of MI Over Time Controlled Additive Comparative MARMITE

23. Effect size was not predicted by: • Number of MI attributes mentioned • Methodological quality of study, except Use of a manual to guide MI did predict effect size: • Studies not using a manual d = .65 • Studies using a manual d = .37 • Demographic characteristics, except: • Anglo/Caucasian samples d = .39 • Minority samples d = .79 MARMITE

24. Effect size varied with outcome measures Alcohol: • Quantity of drinking d = .30 • Frequency of drinking d = .31 • BAC estimates d = .22 • Negative consequences d = .08 HIV Risk: • Knowledge d = 1.46 • Behavioral Intentions d = .88 • Sexual risk-taking d = .07 MARMITE

25. Mean Combined Effect Size by Problem Area (N=72 Clinical Trials) MARMITE

26. Conclusions 1. Robust and enduring effects when MI is added at the beginning of treatment • MI increases treatment retention • MI increases treatment adherence • MI increases staff-perceived motivation MARMITE

27. Conclusions 2. The effects of motivational interviewing emerge relatively quickly (This is also true of other treatments) Project MATCH Outcomes MARMITE

28. Conclusions 2a. The effects of motivational interviewing emerge relatively quickly • This may not be true for certain problem areas or dependent measures where “sleeper” effects occur (e.g., effects of diet and exercise) MARMITE

29. Conclusions 3. The between-group effects of motivational interviewing tend to diminish over 12 months • This is also true of other treatments • Between-group differences diminish in part because control/comparison groups “catch up” over time • This may not be true of MI’s additive effects with other treatment MARMITE

30. Conclusions 4. The effects of MI are highly variable across sites and providers • This is also true of other treatments, but may be more true with MI • Provider baseline characteristics do not predict effectiveness with MI • Treatment process variables do • Manuals may not be a good idea MARMITE