Complex sentence: He completed his residency in psychiatry at Massachusetts General Hospital in Boston, from 1992-1994 and was chief resident of the MGH inpatient psychiatry unit in 1995.
Split into simpler sentences: He completed his residency in psychiatry at Massachusetts General Hospital (MGH) in Boston, from 1992 until 1994. He was then chief resident of the MGH inpatient psychiatry unit in 1995.