In psychiatry, mindfullness has been mostly used for mood and anxiety disorders. It seems that researchers and clinicians have been more reluctant to examine the effects of mindfulness in people with psychotic disorders.
The following is a potpuri of relevant material. I hope some of it helps.
Cahn, BR, & Polich, J. (2006). Meditation states and traits: EEG, ERP, and neuroimaging studies. Psychological Bulletin, 132(2), 180.
Ellett, L., Freeman, D, & Garety, PA. (2008). The psychological effect of an urban environment on individuals with persecutory delusions: the Camberwell walk study. Schizophrenia Research, 99(1-3), 77-84. doi: 10.1016/j.schres.2007.10.027 (this uses 'mindfulness as a control study)
Gaylord, C., Orme-Johnson, D. & Travis, F. The Effects of the Transcendental Mediation Technique and Progressive Muscle Relaxation on Eeg Coherence, Stress Reactivity, and Mental Health in Black Adults. International Journal of Neuroscience 46, 77-86, doi:10.3109/00207458908991618 (1989).
Kuijpers, HJH, van der Heijden, F, Tuinier, S, & Verhoeven, WMA. (2007). Meditation-induced psychosis. Psychopathology, 40(6), 461-464.
Manna, A., Raffone, A., Perrucci, M. G., Nardo, D., Ferretti, A., Tartaro, A., . . . Romani, G. L. (2010). Neural correlates of focused attention and cognitive monitoring in meditation. Brain Research Bulletin, 82(1-2), 46-56. doi: 10.1016/j.brainresbull.2010.03.001
Sethi, S, & Bhargava, SC. (2003). Relationship of meditation and psychosis: case studies. Australasian Psychiatry, 37(3), 382-382.
Yamamoto, Shin, Kitamura, Yoshihiro, Yamada, Norihito, Nakashima, Yoshihiko, & Kuroda, Shigetoshi. (2006). Medial Prefrontal Cortex and Anterior Cingulate Cortex in the Generation of Alpha Activity Induced by Transcendental Meditation : A Magnetoencephalographic Study. Acta Medica Okayama, 60(1), 51-58.
Vancampfort, Davy, Probst, Michel, Helvik Skjaerven, Liv, Catalán-Matamoros, Daniel, Lundvik-Gyllensten, Amanda, Gómez-Conesa, Antonia, . . . De Hert, Marc. (2011). Systematic Review of the Benefits of Physical Therapy Within a Multidisciplinary Care Approach for People With Schizophrenia. Physical Therapy. doi: 10.2522/ptj.20110218
For a informed answer please contact the following mail: [email protected]. Professor Ostacoli is the expert in the department I have run for twenty five years.