Effectiveness & Cost-effectiveness of Internet-delivered Interventions for Depression and Anxiety Disorders in IAPT

Depression and anxiety are common mental health problems. There are effective treatments for depression and anxiety and one of these is talking therapies using cognitive behaviour therapy (CBT). In recent years CBT has been transferred to online delivery methods and these interventions have proven successful for people being treated with symptoms of depression and anxiety. The current study will utilise a randomised controlled trial design, where the majority (n=240) of participants will be allocated to the immediate treatment (internet-delivered CBT for either depression or anxiety), and a smaller number (n=120) will be allocated to a waiting list. The waiting list group will receive treatment after an eight week wait. This design helps us to understand that any changes in symptoms in the treatment group will be likely due to the treatment they received compared to the waiting list. A sample size of 360 participants is proposed and has been adjusted to ameliorate against patient dropout. Follow-up and maintenance of any positive changes in symptoms is very important in CBT for depression and anxiety, simply because some people can have a relapse of symptoms. We will therefore follow-up the treatment group for 3, 6, 9 and 12 months to assess maintenance of positive gains from treatment. The study also seeks to investigate the cost effectiveness of the treatments.