Association between painful physical symptoms and clinical outcomes in East Asian patients with major depressive disorder: a 3-month prospective observational study by Ang, Q.Q., Wing, Y.K., He, Y., Sulaiman, A., Chiu, N.Y., Shen, Y.C., Wang, G., Zhang, C., Lee, K.H., Singh, P., Granger, R.E., Raskin, J., Dossenbach, M.