Psychological Medicine

Review Article

Collateral outcomes in e-mental health: a systematic review of the evidence for added benefits of computerized cognitive behavior therapy interventions for mental health

P. Musiata1 c1 and N. Tarriera1

a1 Department of Psychology, Institute of Psychiatry, King's College London, UK


Background. E-mental health is a growing research field and an increasing number of computerized cognitive behavior therapy (cCBT) interventions are available for numerous mental health issues. Such interventions are often claimed to have added benefits, or collateral outcomes, when compared with traditional delivery platforms. Our aim was to systematically review the evidence of the cost-effectiveness, geographic flexibility, time flexibility, waiting time for treatment, stigma, therapist time, effects on help-seeking and treatment satisfaction of cCBT interventions for mental health.

Method. The electronic databases Medline and Web of Science were searched for peer-reviewed controlled trials investigating collateral outcomes in computerized and internet-based CBT.

Results. The literature search identified 101 published papers (95 studies), which were included in this review. The results suggest that cCBT interventions are cost-effective and often cheaper than usual care. Limited evidence was found with regard to geographic flexibility, time flexibility, waiting time for treatment, stigma and the effects on help-seeking. Personal support in cCBT was found to take many forms, was not limited only to therapists, and seemed to increase treatment adherence and reduce attrition. Treatment satisfaction with cCBT was found to be high, but more research on attrition due to dissatisfaction is required.

Conclusions. Although the results of this systematic review on the collateral outcomes provide support for the potential of cCBT, these outcomes need to be better assessed within individual e-mental health studies.

(Received May 09 2013)

(Revised January 07 2014)

(Accepted January 16 2014)

(Online publication February 19 2014)

Key words

  • Advantages;
  • CBT;
  • e-health;
  • e-mental health;
  • internet;
  • literature review;
  • systematic review


c1 Address for correspondence: P. Musiat, Ph.D., Institute of Psychiatry, PO Box 077, De Crespigny Park, London SE5 8AF, UK. (Email: