Psychological Medicine

Original Article

Internet-based cognitive behavioural therapy for subthreshold depression in people over 50 years old: a randomized controlled clinical trial

VIOLA SPEKa1a2 c1, IVAN NYKLÍČEKa1, NIELS SMITSa3, PIM CUIJPERSa3, HELEEN RIPERa4, JULES KEYZERa2 and VICTOR POPa1a2

a1 Department of Psychology and Health, Tilburg University, The Netherlands

a2 Diagnostic Centre Eindhoven, The Netherlands

a3 Department of Clinical Psychology, Vrije Universiteit Amsterdam, The Netherlands

a4 Trimbos-instituut, Netherlands Institute of Mental Health and Addiction, The Netherlands

ABSTRACT

Background Subthreshold depression is a highly prevalent condition and a risk factor for developing a major depressive episode. Internet-based cognitive behaviour therapy may be a promising approach for the treatment of subthreshold depression. The current study had two aims: (1) to determine whether an internet-based cognitive behaviour therapy intervention and a group cognitive behaviour therapy intervention are more effective than a waiting-list control group; and (2) to determine whether the effect of the internet-based cognitive behaviour therapy differs from the group cognitive behaviour therapy intervention.

Method A total of 191 women and 110 men with subthreshold depression were randomized into internet-based treatment, group cognitive behaviour therapy (Lewinsohn's Coping With Depression course), or a waiting-list control condition. The main outcome measure was treatment response after 10 weeks, defined as the difference in pre- and post-treatment scores on the Beck Depression Inventory (BDI). Missing data, a major limitation of this study, were imputed using the Multiple Imputation (MI) procedure Data Augmentation.

Results In the waiting-list control group, we found a pre- to post-improvement effect size of 0·45, which was 0·65 in the group cognitive behaviour therapy condition and 1·00 within the internet-based treatment condition. Helmert contrasts showed a significant difference between the waiting-list condition and the two treatment conditions (p=0·04) and no significant difference between both treatment conditions (p=0·62).

Conclusions An internet-based intervention may be at least as effective as a commonly used group cognitive behaviour therapy intervention for subthreshold depression in people over 50 years of age.

(Online publication April 30 2007)

Correspondence

c1 Address for correspondence: Viola Spek, Tilburg University, PO Box 90153, 5000 LE Tilburg, The Netherlands. (Email: v.r.m.spek@uvt.nl)

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