Personalised transcranial direct current stimulation to reduce daily loneliness in people with subthreshold depression

Objectives: To evaluate the effects of multi-session personalised tDCS on real-life loneliness, mood and depressiveness in people with subthreshold depression. Hypothesis to be tested: We test whether people would rate more positive for social stimuli immediately after and after 3 months of tDCS interventions; whether the tDCS interventions would reduce loneliness, negative mood, depression symptoms, bringing positive change to neural correlates; whether changes induced by personalised tDCS would be greater than the conventional tDCS; and whether the more positive ratings for social stimuli after tDCS interventions would be associated with the change in loneliness, mood, depression symptoms, and neural correlates. Design and subjects: A randomised controlled trial is proposed and subjects are individuals with subthreshold depression. Instruments: Validated tests and questionnaires will be used. Brain activations and connectivity will be acquired using a 3.0 Tesla MRI scanner. Interventions: Participants will be randomly allocated to either the personlised tDCS group (individualised stimulation site), the conventional tDCS group (F3 as stimulation site), or the sham control group to receive 10 sessions of tDCS. Main outcome measures: Loneliness, mood, depression symptoms, brain activations and connectivity are the main outcome measures. Data analysis: Linear mixed models will be setup with groups, days, timepoints (pre-, immediately after, and 3 months after intervention), and their interaction as fixed factors, subjects as random intercepts. Expected results: It is expected that both personalised and conventional tDCS will bring positive effects on people’s loneliness and depressiveness, with the effects larger in personalised tDCS.

Funding Source: HKSAR Govt Related Organizations - Health and Medical Research Fund (HMRF)