E-Health intervention for subthreshold depression: Reach and two-year effects of a randomized controlled trial

Background: There is evidence for e-Health interventions for full-blown depression. Little is known regarding commonly untreated subthreshold depression in primary care. This randomized controlled multi-centre trial assessed reach and two-year-effects of a proactive e-Health intervention (ActiLife) for patients with subthreshold depression. Methods: Primary care and hospital patients were screened for subthreshold depression. Over 6 months, ActiLife participants received three individualized feedback letters and weekly messages promoting self-help strategies against depression, e.g., dealing with unhelpful thoughts or behavioural activation. The primary outcome depressive symptom severity (Patient Health Questionnaire;PHQ-8) and secondary outcomes were assessed 6, 12 and 24 months. Results: Of those invited, n = 618(49.2 %) agreed to participate. Of them, 456 completed the baseline interview and were randomized to ActiLife (n = 227) or assessment only (n = 226). Generalised estimation equation analyses adjusting for site, setting and baseline depression revealed that depressive symptom severity declined over time, with no significant group differences at 6 (mean difference = 0.47 points; d = 0.12) and 24 months (mean difference = −0.05 points; d = −0.01). Potential adverse effects were observed at 12 months, with higher depressive symptom severity for ActiLife than control participants (mean difference = 1.33 points; d = 0.35). No significant differences in rates of reliable deterioration or reliable improvement of depressive symptoms were observed. ActiLife increased applied self-help strategies at 6 (mean difference = 0.32; d = 0.27) and 24 months (mean difference = 0.22; d = 0.19), but not at 12 months (mean difference = 0.18; d = 0.15). Limitations: Self-report measures and lack of information on patients' mental health treatment. Discussion: ActiLife yielded satisfactory reach and increased the use of self-help strategies. Data were inconclusive in terms of depressive symptom changes.