A 3.5-year follow-up of Internet-delivered cognitive behavior therapy for major depression

Background: Internet-delivered cognitive behavior therapy (ICBT) for major depression has been tested in several trials, but only with follow-ups up to 1.5 years. Aim: The aim of this study was to evaluate the outcome of ICBT 3.5 years after treatment completion. Methods: A total of 88 people with major depression were randomized to either guided self-help or e-mail therapy in the original trial. One-third was initially on a waiting-list. Treatment was provided for eight weeks and in this report long-term follow-up data were collected. Also included were data from post-treatment and six-month follow-up. A total of 58% (51/88) completed the 3.5-year follow-up. Analyses were performed using a random effects repeated measures piecewise growth model to estimate trajectory shape over time and account for missing data. Results: Results showed continued lowered scores on the Beck Depression Inventory (BDI). No differences were found between the treatment conditions. A large proportion of participants (55%) had sought and received additional treatments in the follow-up period. A majority (56.9%) of participants had a BDI score lower than 10 at the 3.5-year follow-up. Conclusions: People with mild to moderate major depression may benefit from ICBT 3.5-years after treatment completion.