Internet-Based Cognitive Behavioural Therapy (iCBT) for Anxiety and Depression in Singapore

1. Quantitative Study - Patients Inclusion Criteria: * Age ≥21 years * Tier 2 - 3 depression and/or anxiety based on PHQ-9 and GAD-7 scores * PHQ-9 score of 5 to 19 * GAD-7 score of 5 to 14 * Able to provide informed consent Exclusion Criteria: * Unable to read or understand English (Primary 6 level) * Unable to use the internet (e.g. due to lack of internet access or insufficient digital literacy) * Does not possess a mobile device or is not able to access the iCBT application * Actively experiencing psychosis * Suspected with personality disorder * Primary concern is obsessive compulsive disorder (OCD) * Tier 4 patients with severe depression or anxiety * PHQ-9 score of 20 and above * GAD-7 score of 15 and above * Any suicidal risk or ideation * PHQ-9 Question 9 score of more than 2 2. Qualitative Study - Service Providers Inclusion Criteria: * Are currently or previously have been involved in the delivery, supervision, or implementation of the iCBT programme * Have had direct experience supporting patients enrolled in the study * Able to provide informed consent Exclusion Criteria: * Have no direct involvement in the iCBT programme; or * Have had insufficient exposure to the programme, defined as managing fewer than one referred case or less than one month of involvement at the time of recruitment. * Conflict of interest or Supervisory Hierarchy Concerns - Individuals whose participation may create perceived coercion or introduce bias * Inability to provide informed consent