According to the book, when did Donald begin to show signs of psychosis?

Donald, the Galvin's eldest son, began showing signs of psychosis while in college. Ill-equipped medically, financially, and psychologically to deal with their son's issues, Don and Mimi hoped they would resolve themselves. Donald's condition continued to deteriorate over the years, however, to the point where he tried to murder his wife and kill himself. His attempt failed and he soon fell into a cycle of circulating between living at home with his parents and being committed to state hospitals. This cycle would last decades and Donald's presence in the family home would come to be a source of violence, tension, and fear, particularly for his younger siblings