Discussing the characteristics of men and women of genius, he writes:
This marked tendency to melancholy among persons of intellectual aptitude is no new observation, but was indeed one of the very earliest points noted concerning men of genius. ... It is not altogether difficult to account for this phenomenon. ...He continues by suggesting that persons of intellectual aptitude tend to be anxious, and ill-adapted to society, and that these factors feed into their melancholy. He also mentions the sedentary and ‘nerve-exhausting’ nature of the kind of work in which they are likely to be engaged, such work producing or exacerbating ‘moods of depression’.
Finally, Ellis mentions one factor which tends to get ignored in modern explanations of the apparent predisposition of genius to suffering from ‘melancholy’:
Another cause that serves largely to accentuate the tendency of men of genius to melancholy is the attitude of the world to them. Every original worker in intellectual fields, every man who makes some new thing, is certain to arouse hostility when he does not meet with indifference.Havelock Ellis, A Study of British Genius, London: Hurst and Blackett, 1904, pp.220-222.
He sets out on his chosen path ... content to work in laborious solitude and to wait, and when at last he turns to his fellows, saying, ‘See what I have done for you!’ he often finds that he has to meet only the sneering prejudices of the few who might have comprehended, and the absolute indifference of the many who are too absorbed in the daily struggle for bread to comprehend any intellectual achievement.