To the Editor: I’m writing in response to the recent article by Gabriele S. Leverich, M.S.W., L.C.S.W.-C., and colleagues regarding mood switches.
If the rate of threshold switches was not different between bupropion, sertraline, and venlafaxine, then the marked difference (between the three drugs) in the ratio between threshold and subthreshold switches must be because of the fact that there were fewer subthreshold switches with venlafaxine. There is some theoretical rationale for thinking that venlafaxine might be more likely to induce switches, but the fact that there were less subthreshold switches with venlafaxine does not support this theory. I believe, therefore, that Figure 3 and the discussion are somewhat misleading in that the data do not indicate a greater likelihood for venlafaxine to cause switches. Rather, the data suggest that venlafaxine is less likely to cause subthreshold switches, which is probably not a meaningful finding.
1.Leverich GS, Altshuler LL, Frye MA, Suppes T, McElroy SL, Keck PE Jr, Kupka RW, Denicoff KD, Nolen WA, Grunze H, Martinez MI, Post RM: Risk of switch in mood polarity to hypomania or mania in patients with bipolar depression during acute and continuation trials of venlafaxine, sertraline, and bupropion as adjuncts to mood stabilizers. Am J Psychiatry 2006; 163:232–239