Hi kindredspirit, The evidence base indicating that psychological factors causally influence physical illness is overwhelming to say the least. When stressed (or if someone experiences prolonged negative mental states: for example when someone ruminates on mental issues), the hypothalamic-pituitary-adrenal axis gets activated continuously resulting in physiological events and biological clinical manifestations. Even experimental studies have shown this – see the following review: Marsland, A.L., et al. (2017). The effects of acute psychological stress on circulating and stimulated inflammatory markers: a systematic review and meta-analysis. Brain Behav. Immun. 64, 208–219. Also please see the following articles: Kelly, S.J., Ismail, M., 2015. Stress and type 2 diabetes: a review of how stress contributes to the development of type 2 diabetes. Annu. Rev. Publ. Health 36, 441–462. Liu, Y.Z., Wang, Y.X., Jiang, C.L., 2017. Inflammation: the common pathway of stressrelated diseases. Front. Hum. Neurosci. 11, 316. Wirtz, P.H., von K.nel, R., 2017. Psychological stress, inflammation, and coronary heart disease. Curr. Cardiol. Rep. 19 (11), 111. I can provide additional evidence and references if you like.