Barrett is a 1957 graduate of the Columbia University College of Physicians and Surgeons and completed his psychiatry residency in 1961. In 1967 and 1968 he completed part of a correspondence course in American Law and Procedure at La Salle Extension University (Chicago). He was a practicing physician until retiring from active practice in 1993. , his medical license was listed as "Expired" in good standing: "No disciplinary actions were found for this license." A longtime resident of Allentown, Pennsylvania, Barrett now resides in Chapel Hill, North Carolina.