Manfred F. R. Kets de Vries explores how to use writing to process painful experiences: 

The unconscious working of the brain makes interpretation of what a painful experience is all about difficult. We all have an inner world of thoughts and sensations, habits, fantasies, and dreams, and much of what happens to us is beyond conscious awareness. This makes many of us strangers to ourselves, unaware of how we truly feel at any one moment of our lives. Indeed, much of our behavior is automatic; we tend to resort to repetitive habits and attitudes that don’t really express who we are, or what we want to become.

To take the journey into our interior—to understand ourselves better—we need to help our unconscious to construct new meaning out of our experiences. Reflective writing about a painful experience becomes very complementary to talking about it because it engages a different part of the brain. Brain scans suggest that talking is more related to the right than the left hemisphere. As writing has a greater influence on the left hemisphere, it may stimulate parts of the brain that are not affected by talking.

What we get out of reflective writing, therefore, may be more explicit and analytic than what we get out of talking. Talking uses the part of the brain that seems to be more associated with what we think of as our unconscious mind and what we say may to a large extent be determined by habits of thought so deeply embedded that we are no longer aware of them. Our written judgments and interpretations, which engage more the conscious part of our brain, are likely be less formulaic and much more thoughtful than merely talking about it.