To the catalogue of anxieties her patients explore during therapy — marriage, children, and careers — psychologist Alison Howard is now listening to a new source of stress: the political rise of Donald Trump. In recent days, at least two patients have invoked the Republican front-runner, including one who talked at length about being disturbed that Trump can be so divisive and popular at the same time, said Howard, who practices in the District. What had happened to Trump during his childhood, the patient wanted to know, to make him such a “bad person?” “He has stirred people up,” Howard...