Author's response to reviews Title: Suicide and unintentional poisoning mortality trends in the United States, 1987-2006: Two unrelated phenomena? Authors:

conclusions: I am not clear what “rapidly increasing potential for suicide misclassification” means? Suggest re-phrase, or alternatively delete the latter half of this sentence. This opening sentence now reads: “The official decline in the suicide rate between 1987 and 2000 may have been a partial artifact of misclassification of non-elderly suicides within unintentional poisoning mortality.” Much of the paper depends on discussion of relative changes, it would be useful, from time to time, to present absolute rates (see first 3 lines of results section in abstract) Sentences 1-3 of the Results section of the Abstract now read as follows: “The official US suicide rate declined 19% between 1987 and 2000, from 12.71 to 10.43 deaths per 100,000 population. It then increased to 11.15 deaths per 100,000 by 2006, a 5% rise. By contrast to these much smaller rate changes for suicide, the unintentional poisoning mortality rate rose more than fourfold between 1987 and 2006, from 2.19 to 9.22 deaths per 100,000.” Sentences 2—7 in the main Results section now read: “The suicide rate declined 19% between 1987 and 2000, from 12.71 to 10.43 deaths per 100,000 population. It then increased to 11.15 deaths per 100,000 by 2006, a 5% rise. By contrast, the unintentional poisoning mortality rate increased more than fourfold over our observation period, from 2.19 to 9.22 deaths per 100,000. After rising rather steadily between 1987 and 2000, this rate then accelerated sharply as the suicide rate commenced its modest increase. Following an early dip, the rate for injury mortality of undetermined intent ascended over most of the observation period, from 1.24 to 1.72 deaths per 100,000. When we distinguished poisoning mortality by intentionality, the suicide poisoning rate showed decline from its high of 2.61 deaths per 100,000 in 1987 (Figure 2).” Page 5 para 2sentence in bold. I’m not sure I agree with the suggestion that deaths coded as undetermined poisoning deaths are misclassified. This ICD category is being used because of the particular difficulty in classifying possible suicides due to poisoning. We have deleted that part of the sentence.