Patients who respond to ECT enter Phase II and add lithium to either nortriptyline or venlafaxine within 1-3 days of the last ECT. Clinical and side effect evaluations and blood level determinations are conducted weekly for the first month, every 2 weeks until Week 12, and every 4 weeks for the remaining 12 weeks. Following any indication of relapse, patients are monitored more intensively and are re-evaluated within 1 week. The neurocognitive battery is readministered to all patients at 2 and 6 months after the acute ECT course, regardless of ECT clinical outcome.