Can keeping a journal help keep me on track?

I keep a journal. Unfortunately, my journal-keeping is, at best, erratic, as is its purpose. Sometimes, I use it to make notes on story ideas but more often than not, it is my place to vent, to complain about what is going wrong in my life, to give voice (if only in written form) to the worries and fears that dog my footsteps during the day and plague me at night.

I know that there are writers who use their journal for more work-related notes, who believe, as John Jerome (author of The Writing...