Efficacy of Internet based Cognitive Behavioral Therapy for depression and anxiety disappointing. In a recent meta-analysis CBT for depression and anxiety was modestly effective compared to placebo, care as usual, or waiting list conditions. There was also a significant heterogeneity between trials.
Trials studying the same question are unlikely to have the same outcomes on the basis of sampling error. A difference between trials may be due to chance. It is important to know whether discrepancies between trials are greater than we would expect by chance. With heterogeneity the results of various trials are more different than one would expect by chance alone. In short the trials are different.
The authors next analyzed the trials with CBT for depression and anxiety separately (post hoc analysis). Again the effect size for depression treatment with CBT compared to the control conditions was small. CBT did not make the patients much better. Again there was significant heterogeneity. This heterogeneity could be accounted for by 1 single trial. This trial combined CBT with individual support. Maybe internet based CBT for depression with therapist support is efficacious. This lessens the advantages of Internet based CBT.
Advantages of Internet based CBT
3. avoiding the stigma of visiting a psychiatrist
4. treatment at any time and place
5. work at your own pace
6. review the material as often as as desired
7. reduction of therapist time
8. reach people through the Internet who might otherwise not receive treatment
Disadvantages of Internet based CBT:
1. No control on using the intervention
2. treatment sessions can be postponed infinitely
3. really on your own
4. can seem quite impersonal to participants
Levels of therapist involvement:
1. no assistance
2. contact by e-mail or telephone
3. face to face contact between sessions
Further research should focus on the efficacy of the amount of therapist involvement with the Internet based CBT for depression.
For anxiety the CBT had a large effect size and very low heterogeneity. It is hard to understand why Internet based CBT seems to work better for anxiety disorders compared to depression.
Limitations of this meta-analysis
1. small number of studies: 5 for depression, 7 for anxiety disorders
2. the post hoc analysis with subgroups such as depression and anxiety disorders resulted in in smaller groups and the power declined.
3. Uneven distribution of numbers of subjects across studies, the studies on depression all had large numbers of subjects, the studies on anxiety disorders all had small numbers of subjects
4. studies used different inclusion criteria for participants
Internet-based cognitive behaviour therapy for symptoms of depression and anxiety: a meta-analysis.
Authors: Spek V, Cuijpers P, Nyklícek I, Riper H, Keyzer J, Pop V
Journal: Psychol Med, 37 (3): 319-28, 2007