APOE and major depressive disorder: This may be attributable to two reasons: (i) the possible risk of harm to patients (e.g., increased anxiety or depression levels (Green et al. 2009; Bemelmans et al. 2016; Alber et al. 2022)) following the disclosure of results may not be sufficiently acknowledged, and (ii) the invasiveness of specimen sampling for APOE testing (e.g., sampling of blood, hair, or buccal mucosa) is limited.