A Longitudinal Follow-Up Study on Predicting Major Depressive Disorder From Rest-Activity Rhythm Profiles

Can Rest-Activity Rhythm Profiles Predict Major Depressive Disorder? A Longitudinal Follow-up Study

This proposed study will be a longitudinal follow-up study of a case-control study of 160 participants (CREC Ref: 2023.234). This study aims to follow up on the trajectory of depression and rest-activity rhythm (RAR) disruptions, as well as examine their association over time. The investigators aim to identify distinctive RAR profiles of MDD using the data from the original project and hypothesize that two or more groups will be identified based on individual RAR variables using cluster analysis. The investigators hypothesize that significant differences in depressive symptom severity, sleep quality, and other outcome measures collected in this follow-up will be found between the clustered groups. Individuals exhibiting the most disrupted RAR profiles are hypothesized to have the greatest deterioration in depression symptom severity and other outcome measures. The investigators also hypothesize that people persisting with MDD will exhibit greater disruptions in RAR compared to those without MDD at the follow-up. Furthermore, the investigators will examine whether individual RAR parameters are longitudinally associated with changes in depression symptom severity and other outcome measures.

Inclusion Criteria:

• Hong Kong residents aged 18 to 70 years
• Chinese language fluency
• Accessibility to an Internet-enabled mobile device
• A willingness to provide informed consent and comply with the study protocol

Exclusion Criteria:

• Severe medical or neurocognitive disorders that make participation unsuitable
• History of electroconvulsive therapy (ECT)
• An unstable use of psychotropic drugs (medication use has to remain stable for at least 6 weeks before baseline assessment)
• Current involvement in any psychological treatment program that targets depression and/or sleep problems
• The investigators will not exclude those with current suicidal risks (i.e., non-fleeting intent or plan), which is a common symptom of MDD. However, if serious suicidal risk (i.e., PHQ-9 Item 9 score > 2) is identified, the participant will be referred to the PI (a clinical psychologist) for further assessment and professional mental health services if deemed necessary.

Exclusion criteria for actigraphy assessment:

• Shift work, pregnancy, work, family, or other commitments that interfere with regular sleep-wake patterns
• Presence of other untreated sleep disorders, including narcolepsy, obstructive sleep apnoea (OSA), and restless leg syndrome (RLS)/periodic leg movement disorder (PLMD) based on the cut-off scores of individual sections in SLEEP-50 (narcolepsy ≥ 7; OSA ≥ 15; RLS/PLMD ≥ 7)