The purpose of this study is to evaluate the efficacy of ketamine in reducing depressive symptoms in subjects with a comorbid major depressive episode and alcohol dependence. The investigators hypothesize the following for the present study:

A single dose of ketamine will induce a rapid, robust and sustained reduction in depressive symptoms in subjects with a comorbid major depressive episode and alcohol dependence relative to placebo as defined by change in Hamilton Depression Rating Scale total scores at 72 hours post infusion.

A single dose of ketamine can be delivered safely, with minimal adverse events or complications, in subjects with a comorbid major depressive episode and alcohol dependence.