The effect of depression and anxiety symptom severity on clinical outcomes and app use in digital mental health treatments: Meta-regression of three trials.

A large number of trials have consistently shown that guided digital mental health treatments (DMHTs) are effective for depression and anxiety. As DMHTs are adopted by healthcare organizations, payers, and employers, they are often considered most appropriate for people with mild-to-moderate levels of symptom severity. Thus, the aim of this study was to examine the effects of symptom severity on depression and anxiety outcomes and app use across three trials of a guided DMHT, IntelliCare. Participants were categorized into mild, moderate, moderately severe, and severe symptom severity groups on depression and anxiety. All symptom severity groups showed significant reductions in depression and anxiety in a clear ordinal pattern, with the mild symptom severity group showing the smallest changes and the severe symptom group showing the largest improvements. Those with the lowest levels of educational attainment showed the largest symptom improvement. Baseline symptom severity was not significantly related to app use. App use was significantly related to depression and anxiety outcomes. These findings suggest that depression and anxiety symptom severity is not useful in determining who should be referred to a guided DMHT.