I read about this a decade or two ago in a book by Louise Hay. The cause can be from 'pressure' in life such as deadlines or other related stress such as too much to do in too little time. At that time I called clients and got more reasonable timelines. My haemorrhoids went away.
I believe that we are not all created equal, and the cause of a problem for one is not necessarily the cause for another. I, for one, do not have a yeast problem, as confirmed by a naturopath, but I recently developed a haemorrhoid and realized I have let pressures creep up on me. I knew what I had to do to remedy the situation.
I hope this information helps someone else.