Attempted suicide by insulin overdose in insulin-requiring diabetics

Four cases of suicidal insulin overdose in insulin-requiring diabetics presented to one hospital in three years. In three cases there was a history of depression; but despite huge doses of insulin (3,000 and 1,500 units) in two, no patient died and only one had residual signs of clinical brain damage. The estimated plasma insulin level was not well correlated with the severity of the hypoglycaemia. It is probable that suicidal insulin overdose is more common than reports in the literature suggest, and may often be unrecognized. The dissociation between huge doses of insulin and the severity of the subsequent hypoglycaemia in diabetics is unexplained.