Primarily, the interventions should be labelled motivational interviewing
(M)) or motivational enhancement therapy (MET). The
intervention could basically be offered in three ways: (1) as a standalone
therapy, (2) MI integrated with another therapy, or (3) MI
as a prelude to another therapy (e.g. cognitive behavioral therapy).
Only individual, face-to-face interventions were included.We excluded
group interventions, and interventions not given in person
(e.g. computer-delivered or telephone interventions). Because
most psycho social interventions have many unspecific elements in
common, and because terms like “motivational intervention” and
“motivational interview” not necessarily refers to Miller’s specific
program of MI, we included only studies that reviewed audio or
video recordings to ensure that the intervention given was indeed
MI.
Studies had to include checks of audio- or videotaping of sessions
in order to assess fidelity of treatment.