title: Motivational interviewing: a systematic review and meta-analysis.
abstract: BACKGROUND
  Motivational Interviewing is a well-known, scientifically tested method of counselling clients developed by Miller and Rollnick and viewed as a useful intervention strategy in the treatment of lifestyle problems and disease.
  
  
  OBJECTIVE
  To evaluate the effectiveness of motivational interviewing in different areas of disease and to identify factors shaping outcomes.
  
  
  METHODS
  A systematic review and meta-analysis of randomised controlled trials using motivational interviewing as the intervention.
  
  
  METHODS
  After selection criteria a systematic literature search in 16 databases produced 72 randomised controlled trials the first of which was published in 1991. A quality assessment was made with a validated scale. A meta-analysis was performed as a generic inverse variance meta-analysis.
  
  
  RESULTS
  Meta-analysis showed a significant effect (95% confidence interval) for motivational interviewing for combined effect estimates for body mass index, total blood cholesterol, systolic blood pressure, blood alcohol concentration and standard ethanol content, while combined effect estimates for cigarettes per day and for HbA(1c) were not significant. Motivational interviewing had a significant and clinically relevant effect in approximately three out of four studies, with an equal effect on physiological (72%) and psychological (75%) diseases. Psychologists and physicians obtained an effect in approximately 80% of the studies, while other healthcare providers obtained an effect in 46% of the studies. When using motivational interviewing in brief encounters of 15 minutes, 64% of the studies showed an effect. More than one encounter with the patient ensures the effectiveness of motivational interviewing.
  
  
  CONCLUSIONS
  Motivational interviewing in a scientific setting outperforms traditional advice giving in the treatment of a broad range of behavioural problems and diseases. Large-scale studies are now needed to prove that motivational interviewing can be implemented into daily clinical work in primary and secondary health care.
authors.affiliation: Department and Research Unit of General Practice, University of Aarhus, Denmark. sr@alm.au.dk
authors.forename: Sune
authors.initials: S
authors.lastname: Rubak
authors.forename: Annelli
authors.initials: A
authors.lastname: Sandbaek
authors.forename: Torsten
authors.initials: T
authors.lastname: Lauritzen
authors.forename: Bo
authors.initials: B
authors.lastname: Christensen
mesh_terms: D003625:Data Collection / Q000592:standards; D006801:Humans; D007407:Interviews as Topic / Q000379:methods*; D009042:Motivation; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results