It's important to bear in mind that meditation is a religious practice specifically aimed at causing ego-death. Yogis writing about the practice (before it became big business) freely admit all sorts of horrible-sounding mental side effects, but couch them in religious terms (and encourage the acolyte to push through until they achieve "enlightenment", which they describe as a profoundly nihilist state of being). Thi…
On a personal note, depression is not only about anxiety, or any beliefs about oneself. It may stem from understimulation. In this case, lowering input (as with meditation) is unlikely to help.