While there are positive studies demonstrating associations between APOE-ε4 and depression in the elderly (Caselli et al., 2004; Flicker et al., 2004; Fritze et al., 2011; Krishnan et al., 1996; Rigaud et al., 2001; Stewart et al., 2001), there are also negative reports (Cantillon et al., 1997; Liu et al., 2002; Mauricio et al., 2000; Schmand, Hooijer, Jonker, Lindeboom, & Havekes, 1998; Surtees et al., 2009). The gene discussed is APOE; the disease is major depressive disorder.