Welcome to the nexus!

I think psychedelics can be applied to depression, but I'm not sure under which conditions they will work and under which they won't. I've had personal success in using them against depression (though it was psilocybin not dmt), but I think the success depends on a lot of things other than the substance itself. Generally I would think that a longer experience is really necessary to make the changes necessary to move the mind out of its cycles of depression, so I would think oral dmt would work better.

I've not tried Ayahuasca, but I have tried Pharmahuasca (the extracts taken together) and in my experience there is a difference which is brought on by the interaction of the harmalas. Harmala alkaloids have their own feel and alteration of consciousness (also mildly anti-depressant), they sedate and facilitate an entry into a more dreamy kind of state, which changes the way the dmt-trip envelops you.

Ayahuasca itself often only uses small amounts of dmt containing plant material while being quite high on caapi-content. There are even Ayahuasca brews without any dmt, only with caapi.

I liked pharmahausca a lot, despite the initial nausea, so if you have the chance, do try it. I find it a more wholesome experience.

cheers & love

Enoon