If you take standard psych testing when you are physically ill, it will show somatoform disorder. Psych testing works on well people to some extent. I imagine some pain clinic or IME got you into the psych testing realm. When you answer the questions about symptoms, 'My neck hurts', etc. positively, it will skew your test to 'being somatoform'.

Now, since you have Sjogrens.....it DOES come with neuropathy and potential encephalopathy. Like Lupus, it can produce psychiatric problems via inflammation or vasculitis.

And they won't find that on MMPI (type of psych test)