Smartwatch-supported Internet-delivered Intervention for Depression

All participants will be asked to fill in the Acceptability Questionnaire (AQ) upon consent, at 3 weeks, and at 8 weeks. These measurement points are aligned with Nadal et al. (2020) Technology Acceptance Lifecycle model. The questionnaire is based on the acceptance factors identified by Kim & Park (2012). The wording of the AQ is adapted to the technology in question (smartwatch vs mobile/desktop app). Participants will rate each statement on a 5-point Likert Scale. The 8-week AQ contains a series of open-ended questions for the smartwatch group to explore additional factors that might influence the watch app acceptance (privacy protection, resistance to change, etc.).

Participants in the smartwatch group who have indicated consent in taking part in the follow-up interview will be contacted after answering the final acceptance questionnaire.

The SAT (Richards et al, 2013) will be used to assess patient satisfaction with the intervention. This 5-item questionnaire has been used previously to evaluate different aspects of patient satisfaction and experience with the 'Space from Depression' intervention (Richards et al, 2013).

Score varies from 0 to 20; a higher score indicates a better outcome. The score is informed by 2 open-ended questions at the end of the questionnaire.

The PHQ-9 is a nine-item self-report measure of depression (Kroenke et al, 2001; Spitzer et al, 1999) that has been widely used in research and is employed as a clinical outcome measure in IAPT as part of its minimum dataset. The PHQ-9 items reflect the diagnostic criteria for depression outlined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (A.P. Association, 2013).

Score varies from 0 to 27; a higher score indicates a worse outcome.

The GAD-7 (Spitzer et al, 2006) is used nationally as a screening and outcome measure in IAPT and is part of the minimum dataset. The seven items measuring anxiety symptoms and severity reflect the DSM-Fifth Edition diagnostic criteria for GAD (A.P. Association, 2013).

Score varies from 0 to 21; a higher score indicates a worse outcome.

This is a five-item self-report questionnaire of functional impairment (Mundt et al, 2002) that is employed nationally as an outcome measure in IAPT. It examines the experiential impact of a disorder across different life domains from the perspective of the service users. The questionnaire examines the degree of impairment caused by a disorder on a daily basis across five dimensions: work, social life, home life, private life, and close relationships.

Score varies from 0 to 40; a higher score indicates a worse outcome.

Usage data in terms of time spent in the platform, number of logins, number of tools used, percentage viewed, and number of reviews will be collected. Also, the amount of mood monitor entries, sleep and activity data will be extracted. Approximate activity levels (graded 1 to 5) and sleep patterns will be analyzed to explore the changes over time.