dear, Zoloft can cause anxiety and therefore tremors, as its side effect. The shakes your mom is having is most probably due to the Zoloft here as it wasn t there previously I presume. However, shakes can be due to various other reasons as well. And there are varieties of tremors(shakes), which warrants a proper physical examination. Discontinuation of current medication is not at all a wise thing, because it can precipitate the underlying depression. The exact dose and duration of treatment would had made me better equipped for advice. However, I strongly advice to reconsult your treating psychiatrist. A change in antidepressant may be all that would be needed. thank you. stay healthy