Major depression (MD) and alcohol dependence (AD) are common psychiatric disorders, contribute substantially to global morbidity, and often co-occur (Ferrari et al., 2013; Shield et al., 2013). Epidemiological studies report that individuals with MD are at increased risk for AD and vice versa (Kessler et al., 1997; Swendsen and Merikangas, 2000; Boden and Fergusson, 2011). Leading hypotheses suggest these associations may be due to shared risk factors (genetic and environmental) or causal processes of one disorder leading to the other, such as the self-medication hypothesis of MD (Khantzian, 1997). However, the mechanisms underlying MD-AD dual diagnosis remain unclear.
