The authors examined whether the use of lithium could prevent suicidal behaviour in 81 psychiatric inpatients. There were more cases of completed suicide among the nonlithium group. In the group of suicide attempters, 15 subjects were taking lithium. Considering suicidal behaviour as a whole, it was found that the lithium-taking group had a higher possibility of presenting this behaviour. There were no other differences in correlations between suicidal behaviour & factors such as age & gender.