“…A second method, mindfulness training (e.g., Goyal et al., 2014), teaches the student to focus on their thoughts in the present moment by bringing themselves back (repeatedly) to the present, noticing what is experienced (e.g., “a thought is just a thought, an emotion is just an emotion”), and choosing what to do with it (e.g., “see it for what it is, let it go”). Learning to control where one directs one’s attention is believed to decrease negative biases, modify appraisals of threat, and increase capacity to regulate emotions (see Southwick & Charney, 2012a, 2012b).”
http://www.ptsd.va.gov/professional/newsletters/research-quarterly/V25N4.pdf