As a result of learning disability, Churchill struggled with studies at Harrow School in his early years. So much so that it prompted his headmaster to write several concerned letters to his parents questioning his overall learning abilities. His disruptive behaviour in class suggests he may have suffered from attention deficit disorder. Due to difficulty taking notes, it is believed that he had to memorise his lectures, relying instead on memory that he also employed to deliver his many famous speeches. He also suffered from bi-polar disorder throughout his life.
Source: Graham,J., Shinkfield, A., Smith, K. & Polzin, U., 'Employer benefits and costs of employing a person with a disability', Journal of Vocational Rehabilitation, vol. 17, pp. 251-263.