Letters Section Editor: Robert M. Golub, MD, Senior Editor.
To the Editor: In their study of suicide prevention, Dr Brown and colleagues1 conclude that cognitive therapy reduces the risk for subsequent suicide attempts. We have some methodological concerns that we believe affect this conclusion.
First, 15 (25%) of the participants in the cognitive therapy group and 20 (33%) of the participants in the control group were lost to follow-up. With these relatively large numbers of unknown outcomes, it is difficult to assess whether the study results are accurate estimates of the true effect. As the authors suggest in the “Comment” section of their article, given a small number of patients in each group and a small number of outcome events, a few misclassified or unknown outcomes could have substantial impact on the comparison between the 2 groups. It would be helpful for the authors to provide the results of their sensitivity analysis.
Tepper M, Whitehead J. Cognitive Therapy and Preventing Suicide Attempts. JAMA. 2005;294(22):2847-2848. doi:10.1001/jama.294.22.2847-b