The criteria required for the inclusion of patients into the group studied are described. The 29 patients suffered from recurrent affective disorders. No patient satisfying the criteria for selection was excluded.
Reasons why 11 of the 29 patients could not be included in the double-blind trial are given.
The double-blind trial was performed on the remaining 18 patients. The significance of the difference between the lengths of remissions achieved by the lithium group and the dummy group was measured by the Mann-Whitney U-test. The superiority of lithium over the dummy just failed to be significant at the 5 per cent level, 0.10>p>0.05.
One case of serious toxicity occurred. The patient recovered rapidly and completely. The design and result of the trial is discussed.