Political commitment, not ill health, drove Gramsci from university.
Evidence
During 1913-15 he was desperately ill most of the time, and eventually he was forced to abandon his studies, despite his talent, especially for philology and linguistics generally, and despite the encouragement of several of his teachers. However, there was a more important reason even than his impossible personal situation which finally decided him to leave the university. This was the fact of his growing political commitment. — Antonio Gramsci, Selections from the Prison Notebooks, 43