I was on high dose prescribed ritalin and 150mg effexor (venlafaxine) for years. could this cause dysautonomia years after stopping? constant brain fog...

? related but doubt: direct cause/effect. Depression and other problems treated with Effexor (venlafaxine) often comes with extra "stuff" in terms of abnormal physical phenomena. Our current understanding of this is chicken vs egg. I suspect the problem(s) you have suffered that have required Ritalin and Effexor (venlafaxine) are much more directly related to your symptoms and not having taken meds. Concerned that depression/anxiety present

Hmmm. Not sure: I do not think there are reports of these medicines causing these symptoms, but we should never say never.