October 20, 2003
Question from Conneaut, Ohio, USA:
My 38 year old sister is was diagnosed with diabetes 18 years ago. Within the last year, she has turned into a different person. She puts herself into dangerous situations, has recently stolen a large sum of money from my mom, and she's facing nine felony counts of theft. She was a person who had no record and never did anything wrong. She seems to have become a totally different person and has no concept of reality anymore. Her blood sugar levels are generally high (in the 400s mg/dl [22.2 mmol/L]) because she doesn't keep taking her pills and insulin since she has money problems. Can diabetes, left basically left untreated, have any affect on a person's brain causing behavioral changes like this? Is this behavior caused from something else entirely?
I think that the most probable cause for your sister’s story is that both the poor control of her diabetes and her recent behaviour are due to some form of acute mental illness. It is possible that all this could be due to diabetes, but if this were the case, one would have expected a much longer history of inadequate control and either a story of repeated severe hypoglycemic episodes or of other involvement of small blood vessels especially of the retina or the kidneys.