He attended Mount Sinai Hospital Arthritis Clinic and conducted combined research with the director Dr Harry Spiera.
He linked sociology, anthropology and psychology methods to help address issues in the diagnosis and treatment of various painful disorders affecting various organ systems.
The clinic is primarily designed to serve as a research facility while at the same time offering diagnosis and care for unusual chronic pain disorders.
From 1993 to 1997 he held a joint appointment as clinical professor of public health in the Department of Psychiatry, College of Physicians & Surgeons, Columbia University.
From 1998 to 2001 Marbach held a joint appointment as lecturer at the School of Public Health Division of Sociomedical Sciences and Department of Psychiatry, College of Physicians & Surgeons, Columbia University.