There is a good chance, yes. And it's probably a good reason to stop this trial if that was completely unexpected. But I don't think that that's the last we will hear of this treatment if there is a market for it, which there seems to be.

For example, Isotretinoin https://en.wikipedia.org/wiki/Isotretinoin (known as Accutane/Roaccutane and by other names) is also associated with depression and suicidal behavior. It's still a popular drug used to treat acne, even though that is not a particulary dangerous disease.

I don't know anything about how the pharma industry works, but I'd guess they'll restart the trial, taking depression into account and watching for signs among the participants. And maybe with a lower dosage?