I've had blood tests on and off for years now. One reason is because I was once on lithium so they had to check my levels. Now they do it every 3 to 4 months to see what my A1C is. Wacked out sugar levels can cause emotional problems. I was bipolar 1 long before I got diabetes, so I don't think my bipolar is from my sugar. They also checked my thyroid to see if it was working right, and it was and to think I use to hate needles.