Hi DanR1987, sorry I only just saw your post. For some reason I don't get flagged on my phone.
Just wondered if you have any other autoimmune diseases? Or anyone in your family? I have Hashimoto's, Addisons and now very early LADA. Also have some diabetes in my family (probably both Type 1 and Type 2) I found out I was GAD positive 4 years ago just by an enquisitive endo on a random blood test but my blood sugars were normal, even now I am not officially diabetic by my numbers (HbA1c only just in pre-diabetic range) but my HbA1c has been gradually creeping up over the last few years.
It is possible to be GAD positive and never become diabetic but I don't think any doctor would be able to tell you whether you will or won't. I've been living in LADA limbo for the last 4 years so I feel your pain!
So, what was the conclusion your Neurologist came to? And do you know what the results of your blood tests were that enabled the doc to rule out diabetes (and stiff person syndrome) at this present time?