OBJECTIVE The aim of this study was to conduct a systematic literature search in order to assess effectiveness of computer- and internet-based cognitive behavioural therapy (CCBT). METHODS Medline, Cochrane Library, Web of Science and PsycINFO were searched for relevant articles. Only RCTs were included. Effect sizes were calculated and quality of studies was assessed. RESULTS 16 studies were retrieved and included. Effect sizes depended on therapist time involvement and control group intervention (waiting list vs. active control group) and ranged between 0.0 and 1.1. CONCLUSIONS CCBT provides an effective and potentially cost-effective interventional strategy for depressive disorders. Effects of no and minimal contact therapies are confounded with conditions of control groups and need further investigation. While patients with Major Depression seem to benefit from computer-based therapy with regular therapist contact, it remains unclear whether unattended self-help interventions over the internet are effective for this patient population. However, these interventions are effective in patients with mild to moderate depressive symptomatology. CCBT may serve as a first step of treatment within stepped care approaches and may help to offer treatment to individuals in remote areas and to decrease barriers to seek psychiatric care caused by stigma perception.
