It's possible. Psychedelic drugs should generally not be combined with antidepressants for a variety of reasons.
they are both indoles. that means that they work upon the same neurochemical. Zoloft inhibits the reuptake of serotonin. LSA, the active chemical in morning glories, 'pretends' to be serotonin. Most entheogens are indoles and act upon this mechanism. I suspect that the zoloft would cause the LSA to act for a longer period and act far stonger.
I take Lexapro which is also an SSRI and I have done Morning Glory's many times without any noticeable problems. I haven't done them off of the medication so I have no basis to compare it to, but I honestly think it shouldn't really cause a problem. I would just reccomend that you start off with lower doses at first.
