Writing as therapy? Only lie on the couch if you want to read a good book, not write one

There's a blurry old line between writing and therapy.  I've taught classes where people were unable to finish reading their work because they were crying and in many ways both reading and writing highly-charged literature can be cathartic.

If it's catharsis you are after -- that purging release of emotion, then using your work as a kind of therapy may be a good idea.  If your aim is to write to the very best of your ability, it might be better to do your therapy elsewhere.

I suspect I'm on potentially controversial ground here.  Many feel that their inner demons drive their creativity and provide the passion to write in the first place. I know from my own work that my experience informs the subjects I choose and how I tackle them.  However, my hunch is that unless you confront major personal issues and come to terms with what they have to tell you in some forum other than your story or novel, you will be the servant of them in your writing, rather than the master.  You also risk writing and rewriting the same stuff, because unless you lay your ghosts they keep coming back to haunt you.

Perhaps an added bonus of doing therapy before you write, rather than as part of the process, is that you will have already visited dark places, fascinating, uncomfortable places, but will be (hopefully) be healed enough to write about them, a kind of reporting from the interior, without coming to further harm.