Are effects of depression management training for General Practitioners on patient outcomes mediated by improvements in the process of care?

Background: Depression treatment by General Practitioners (GPs) and patient outcomes improved significantly after a comprehensive 20-h training program of GPs. This study examines whether the effects on patient outcomes are caused by the improvements in the process of care. Methods: Seventeen GPs participated in the training program. A pre-test–post-test design was used. A total of 174 patients (85 pre-test, 89 post-test) aged 18–65 met ICD-10 criteria for recent onset major depression. The main indicator of mediation was a drop in training effect size (η2) on patient outcome after adjustment for individual and combined process of care variables. We evaluated depression-specific (recognition, accurate diagnosis, prescription of antidepressant, adequate antidepressant treatment) and a non-specific process of care variable (communicative skillfulness of the GP) as well as the combination of adequate antidepressant treatment and communicative skillfulness. Patient outcomes were assessed at 3 months and consisted of change in severity of symptomatology, level of daily functioning and activity limitation days from baseline. Results: Depression-specific interventions mediated up to one third of the observed improvement in patient outcome. ‘Adequate dosage and duration of an antidepressant’ explained 36% of the training effect on patient outcome (η2 from 0.044 to 0.028). ‘Communicative skillfulness of the GP’ only was a weak mediator (18% explained; η2 from 0.044 to 0.036). However, the combination of both, that is adequate antidepressant treatment by a communicative skillful GP, proved to be the strongest mediator of the observed training effect on patient outcomes (59% explained; η2 from 0.044 to 0.018). Limitations: The training effects on patient outcomes in this sample were small. Hence, the scope for mediation was limited. Conclusion: GP communication skills are important to enhance depression-specific interventions in bringing about improvements in patient outcomes and should be addressed in GP training programs for the treatment of depression.