Results: We observed a variation of factors which seemed to contribute to the active ingredients. Most prevalent was (eliciting) ‘change talk’, but also factors such as ‘experiencing competency’ and ‘changing sense making’. Since mechanisms of change refer to psychological processes within the patient’s mind, it is impossible to observe these. But we recognised clues for mechanisms of change, the most prevalent mechanism was ‘arguing oneself into change’. The most important conversational techniques are reflections and questions addressing medication adherent behaviour or intentions, which was often (in 74% and 69% of the time respectively) followed by change talk.
Conclusions: Active ingredients of MI seem to consist of a sufficient combination of factors, to which both patient and therapist contribute. This combination may act as an active ingredient and can trigger mechanisms of change. Our study suggests that in particular the patient factors are a pool of factors from which, after proper activation by therapist factors, different combinations can form active ingredients.