A recent development in the medical/mental healthcare sector is the use of online systems to support the delivery of "talking therapies". In effect this innovation is to use internet and mobile device technology to allow a therapist to delivery cognitive behavioural therapy (CBT) (i.e. talking therapy) to a patient over their mobile device via a text-based conversation. CBT is a therapy that teaches the individual to overcome their anxiety and/or depression by breaking their problems down into smaller issues and avoiding negative patterns of behaviour. The applicant, behind this application, provides a digital platform that trains and support the therapist provide these CBT services to a number of NHS Trusts. The current system only links the therapist to the patient via text-based communication. The applicants believe there is the potential to collect additional data that could be extremely useful for the therapist and could dramatically improve the effectiveness of the CBT therapy provision. The enclosed research project aims to collect and explore the potential value of these "digital cognitive and behavioural biomarkers". Examples of these behavioural biomarkers could be: * The physical location of the subject during an anxiety attack; * Patterns of social media use and interaction during bouts of depression. This project will collect substantial volumes of this information from a set of CBT patients. This data will be analysed to determine if there are relationships between these cognitive and behavioural biomarkers and the individuals condition. The project is crucially focused on the implementation of highly advanced software technology to ensure only meaningful, clinically useful, information is fed back to the therapist to improve mental healthcare provision. A further goal of the project is to devise general population mental health screening techniques. It is envisioned that people's mobiles phones can be transformed into early stage mental health screening devices and direct people to appropriate treatment accordingly. Due to the sensitive clinical, ethical and personal nature of this project, the team has taken considerable steps to ensure the project is overseen by external experts and patient representatives. The project will have a Patients Panel, Advisory Group and cybersecurity advisors to ensure the methods used are robust and as safe as possible. Both the lead applicant and supporting partner are highly experienced at addressing privacy concerns, for such patient populations, and pride themselves on meeting best practice requirements.