Patients who have undergone bariatric surgery are at substantially increased risk of suicide, a study from the United States has found. Although the absolute suicide rate (1 in 538) was low, this was much higher than that of the general population. All Pennsylvania residents who underwent bariatric surgery between January 1st 1995 and December 31st 2004 were identified from the comprehensive state records. This data was then matched to mortality data for the period September 1st 1996 to December 28th 2006. Of the 16,683 patients who underwent bariatric surgery, 31 committed suicide during the study period. The suicide rates for men and women were 13.7 and 5.2 per 10,000 person-years respectively. The corresponding age-matched rates for the US population were 2.4 (men) and 0.7 (women) per 10,000 person-years.The true number of suicides is likely to have been significantly higher as a result of the misclassification of suicides as unintentional poisoning. While the official US suicide rate declined by 12% between 1987 and 2006, there was a more than four-fold increase in the number of deaths attributed to unintentional poisoning. 'I would draw two lessons from this study. First, before referring patients for bariatric surgery, we must have a detailed discussion with them regarding both the potential benefits and associated risks of surgery, including the risk that they will ultimately be disappointed with the result. Second, we should ensure that bariatric surgery patients receive adequate support and follow-up, particularly during the second and third postoperative years.'