Koch's achievements, along with the performances of many other East German female athletes, have long been under suspicion that they were achieved with the aid of performance-enhancing drugs.  These drugs were and remain illegal, but were not detectable at the time. In 1991, German anti-drug activists Brigitte Berendonk and Werner Franke , were able to save several doctoral theses and other documents written by scientists working for the East German drug research programme. The documents list the dosage and timetables for the administration of anabolic steroids to many athletes of the former GDR, with one of them being Marita Koch. According to the sources, Koch did use the anabolic steroid Oral-Turinabol (4-Chlorodehydromethyltestosterone) from 1981 to 1984 with dosages ranging from 530 to 1460 mg/year. 
During that period, Soul also became deeply involved in the anti-Vietnam War movement and fought tenaciously and, finally, successfully against induction into military service. Ironically, in 1971, he was to appear in one of the most celebrated anti-war movies of the day, Dalton Trumbo’s Johnny Got His Gun (with Timothy Bottoms and Donald Sutherland). After the collapse of the ‘New Talent Program,’ Soul went freelance and, over the years, starred in many episodic television series, among them The FBI , Dan August , Ironside , Medical Center , Cannon , All in the Family , The Streets of San Francisco , MacMillan and Wife , Perry Mason , Crime Story , The Young Riders (two-parter), and many more.