Learning flow in educational contexts: A meta-analysis of its antecedents and outcomes.

Depression is a widespread mental health disorder that significantly reduces the quality of life (). It is characterized by persistent sadness or loss of motivation for at least two weeks and can severely impact daily functioning, relationships, and work (–). The global burden of depression has risen, especially during and after the COVID-19 pandemic, leading to a 25% increase in prevalence of anxiety and depression (, ). Mounting evidence indicates that depression is a complex condition shaped by both genetic and environmental factors. Twin studies estimate the heritability of depression at 37% (), and large-scale genetic studies have identified hundreds of risk loci (–). Environmental factors include childhood trauma and socioeconomic stress (). This combination of genetic and environmental factors underscores the need to study how these factors interact and their joint contribution. Gene–environment (G × E) interaction studies investigate how genetic and environmental factors interact. A growing body of research suggests that depression is associated with the interaction of traumatic or stressful experiences with genetic factors (–). For example, an interaction between the and extreme life stress has been linked to bipolar depressive episodes (). The serotonin-transporter-linked polymorphic region (), a genetic variant in the serotonin transporter gene (), has been associated with depression only in individuals with a history of stressful life events or childhood maltreatment (). While numerous association studies predicated on depression have described specific genes that interact with traumatic experiences, findings are often inconsistent, with different studies identifying different genes. This inconsistency likely reflects the polygenic and heterogeneous nature of depression, where a broad set of genetic factors may jointly interact with environmental stressors rather than a few dominant genes determining risk. This complexity highlights the need for comprehensive analyses of G × E interactions to improve our understanding of the underlying biological mechanisms.