Influence of Initial Severity of Depression on Effectiveness of Low Intensity Interventions: Meta-analysis of Individual Patient Data
Peter Bower, professor of health services research, Evangelos Kontopantelis, research fellow, Alex Sutton, professor of medical statistics, Tony Kendrick, professor of primary care and dean, David A Richards, professor of mental health services research, Simon Gilbody, professor of psychological medicine & health services research, Sarah Knowles, research fellow, Pim Cuijpers, professor of clinical psychology, Gerhard Andersson, professor of clinical psychology, Helen Christensen, professor and executive director, Björn Meyer, research director and honorary research fellow, Marcus Huibers, professor of psychotherapy, Filip Smit, professor of public mental health, Annemieke van Straten, professor in clinical psychology, Lisanne Warmerdam, research fellow, Michael Barkham, professor of clinical psychology, Linda Bilich, research fellow, Karina Lovell, professor of mental health, Emily Tung-Hsueh Liu, associate professor of clinical psychology
Abstract
Objective To assess how initial severity of depression affects the benefit derived from low intensity interventions for depression.
Design Meta-analysis of individual patient data from 16 datasets comparing low intensity interventions with usual care.
Setting Primary care and community settings.
Participants 2470 patients with depression.
Interventions Low intensity interventions for depression (such as guided self help by means of written materials and limited professional support, and internet delivered interventions).
Main outcome measures Depression outcomes (measured with the Beck Depression Inventory or Center for Epidemiologic Studies Depression Scale), and the effect of initial depression severity on the effects of low intensity interventions.
Results Although patients were referred for low intensity interventions, many had moderate to severe depression at baseline. We found a significant interaction between baseline severity and treatment effect (coefficient −0.1 (95% CI −0.19 to −0.002)), suggesting that patients who are more severely depressed at baseline demonstrate larger treatment effects than those who are less severely depressed. However, the magnitude of the interaction (equivalent to an additional drop of around one point on the Beck Depression Inventory for a one standard deviation increase in initial severity) was small and may not be clinically significant.
Conclusions The data suggest that patients with more severe depression at baseline show at least as much clinical benefit from low intensity interventions as less severely depressed patients and could usefully be offered these interventions as part of a stepped care model.
