It is not evident whether psychological treatment via the internet is non-inferior to corresponding treatment by a therapist.

Internet-based cognitive behavioural therapy (CBT), with the support of a therapist, reduces symptoms in adults with social phobia or mild to moderate major depression, and who have themselves sought this form of treatment. There is some evidence that this also applies to panic disorder and generalised anxiety disorder. Most trials have compared the treatment only with waiting lists and have short follow-up periods. Further trials are needed to assess the effect of treatment in the longer term.

Given our present level of knowledge, internet-based CBT with therapist support may be considered as part of a wider range of psychological methods for these conditions and mainly for patients who are motivated to seek this form of treatment.

Treatment costs for internet-based CBT in the short term are probably lower than for CBT in a group or individually. However, since the effects of these treatment alternatives have not been adequately compared, it is not possible to ascertain which alternative is cost-effective.

It is important to investigate whether this type of treatment can reach people who are in need of care but who are not currently being treated through ordinary health and medical care. In order to further clarify what role internet-based treatment might have in the care of anxiety and mood disorders, it is also important to clarify the extent to which internet-based treatment is requested by patients.

More and larger-scale studies are required in order to assess:

• whether internet-based psychological treatment has an effect that is non-inferior to that of established psychological treatment methods
• what risks might be involved in participating in internet-based treatment
• what effect internet-based psychological treatment has on anxiety and mood disorders in children and adolescents
• the effect of types of internet-based psychological treatment other than CBT with therapist support
• whether there are groups of patients for whom treatment via the internet is more or less appropriate