Negative thoughts can create more stress in our lives. Not only can "negative affect," or being in a bad mood, color our experience so that many of the things we experience seem more stressful and even overwhelming, but our bad mood can be contagious, and can even cause others to treat us in a less friendly way, perpetuating negativity in us and virtually everyone we encounter, to a degree.
This is significantly faster than the years-on-the-couch rate of psychoanalytic therapy, which is what many people still think of when they think of "going to a shrink."
Support for the effectiveness of this approach comes from research on optimistic and pessimistic explanatory styles. It is also revealed by the positive results that come from cognitive therapy for stress, or a mix of cognitive and behavioral therapy.
Cognitive therapy has also been combined with the practice of mindfulness. This created mindfulness-based cognitive therapy (MBCT), which has shown promising effects as well.