We have published a negative study previously of inositol as an augmentation of SSRI failures, enrolling forty-two patients over two years (Nemets et al, 1999). Antidepressant failures are easier to recruit from referring physicians in our center than are untreated patients, whom clinicians are reluctant to refer for new drug studies given the adequacy of standard treatment in 2/3 of them. Thus we estimate that we could enroll 20 patients per year in such a study. Survey of the literature of Li augmentation suggests that 40 phenytoin vs. 40 placebo should give adequate power to detect a significant phenytoin effect if the phenytoin effect is similar to that of lithium.