Olanzapine and Negative and Positive Symptoms

To the Editor: The article by Alex Kopelowicz, M.D., et al. (1) purported to show that olanzapine helps secondary negative symptoms but not primary negative symptoms. However, there seems to be a confound here. The deficit group (primary negative symptoms) not only failed to show improvement in negative symptoms, but it also showed no improvement in positive symptoms. Those with secondary negative symptoms (the nondeficit group) showed significant improvement in positive and negative symptoms. Therefore, one could explain their results not only by pointing to a differential effect of olanzapine on primary and secondary negative symptoms, but also by asserting that negative symptoms in both groups improve only when positive symptoms improve. I realize that by the authors’ definition, these subjects’ primary negative symptoms did not come from positive symptoms, but that assertion lacks empirical proof.