In Sickness and in Power: Illnesses in Heads of Government during the Last 100 Years

Between 1906 and 2008 seven Presidents are judged to have been mentally ill while in office: Theodore Roosevelt (bipolar disorder), Taft (breathing-related sleep disorder), Wilson (major depressive disorder), Coolidge (major depressive disorder), Hoover (major depressive disorder), Johnson (bipolar disorder), and Nixon (alcohol abuse).