Abstract
<title>Abstract</title> <p>Subclinical depression is common, impairing, and associated with elevated risk for major depressive episodes, yet scalable early interventions remain limited. In this randomized waitlist-controlled trial, we evaluated whether an 8-week Group Music and Imagery (GrpMI) intervention was associated with changes in depressive symptoms, emotional working memory, and hippocampal structure in individuals with subclinical depression. Compared to 25 waitlist controls, the intervention group (n = 26) showed significant reductions in HAMD-17 and a relative preservation of left hippocampal volume. Emotional working memory improved within the intervention group but without significant Group × Time interaction for either accuracy or response time. Exploratory analyses combining GrpMI from both groups (following crossover) further identified localized increases in the volumes of the left hippocampal CA3, CA4, and molecular layer of the hippocampus (Molecular Layer HP). These findings provide preliminary multimodal evidence that GrpMI exerts a systemic therapeutic effect, highlighting its potential as a comprehensive early intervention. While the macrostructural changes offer a plausible neurobiological correlate of recovery, larger trials utilizing active control conditions are required to confirm therapeutic efficacy and elucidate the underlying cellular mechanisms.</p>