It is an interesting question. I've personally found that most venting and catharsis leads to repetition and maybe even strengthens existing patterns. Contemporary work on trauma (Bessel van der Kolk, Peter Levine, Gabor Maté) regards catharsis as retraumatizing and works instead with "titration", i.e. re-experiencing and expressing just a little at a time.

On the other hand, I've personally experienced a cathartic process that—as best as one can trace these things—brought real change, so there's no single answer about this.