Special Issue on Computerized Treatments of Depression

There is no mental disorder with a higher disease burden on the population level than major depression. Not only are depressive disorders highly prevalent (Kessler et al., 1994; ESEMED, 2004), they also have a high incidence (Waraich, Goldner, Somers, & Hsu, 2004). Furthermore, they are associated with a considerable loss of quality of life in patients and their relatives (Ustun et al., 2004; Saarni et al., 2007), with increased mortality rates (Cuijpers & Smit, 2002), with high levels of service use, and with enormous economic costs (Berto et al., 2000; Greenberg & Birnbaum, 2005; Smit et al., 2006). The disease burden of depression is higher than the burden associated with diabetes, or all traffic accidents. At this moment major depression is the fourth disorder worldwide in terms of disease burden, and it is expected to be the disorder with the highest disease burden in high-income countries by the year 2030 (Mathers & Loncar, 2006). Internet interventions can be an enormous help in providing evidence-based treatments for depressed patients. Although not all people with a depressive disorder seek professional help, about half of them do (Andrews et al., 2001; Bijl & Ravelli, 2000). This results in huge numbers of patients who have to be treated in primary and mental health care. Internet interventions have the potential to reduce the resources needed for the treatment of these patients, because they can save a considerable part of the therapist’s time, may reduce waiting-lists, and may stimulate efficiency because there is no need to schedule appointments with a therapist. Because the threshold to participate in Internet interventions is low, it may by possible to reach depressed patients in the early stages of their disorder, and prevent these cases from becoming severe and chronic. Internet interventions also have several advantages for patients, including reduced waiting time for a therapist, no travelling time, a reduction of the stigma of going to a therapist, and the possibility of working at their own time and pace. It also stimulates selfmanagement and empowerment of patients, because the basic idea of most Internet interventions is that the patient applies a treatment to him or herself, while the therapist only supports the patients in working through the treatment. There are, of course, also disadvantages and dangers worth mentioning. Patients may not be able to finish a self-help intervention, which may result in a negative experience that could have a detrimental effect on their condition. Also, a patient’s problems may be too severe for an (unsupported) self-help intervention, which may prevent the provision of adequate help. Or the patient may suffer from a different disorder than the one aimed at by the intervention at stake. Most of these advantages and disadvantages of Internet interventions are still hypothetical. Although the number of studies examining these interventions has exploded in the past few years, many issues remain unclear. This issue of Cognitive Behaviour Therapy includes a series of important articles that will definitely help in establishing a better evidence base for Internet interventions. The article from Andersson and Cuijpers in this special issue provides a new meta-analysis of Internet-based and computer-aided treatments for depression. This meta-analysis shows that this type of intervention is clearly effective in the treatment of depression, with effect sizes which are comparable to those found for more traditional types of psychological treatments for depression (Churchill et al., 2001; Cuijpers, van Straten,