I need to know if a person's blood sugar is high is it normal for their behavior and attitude to change? I know someone that is diabetic and recently she just has become so out of charactor. She has become mean, and hard to get along with. She wants to argue a lot. She's demanding, and controlling in somewhat of an aggressive manner. Can anyone tell me if this could be a sign that her sugar is too high, or too low, or is it something else. She never behave in this fashion? Someone Please give me some answers.