The cause seems to be primarily physical, which could be anything from vitamin deficiency to blood sugar or thyroid issues. It is difficult to say that without personally seeing and examining. But depression does tend to aggravate the symptoms and delays recovery.
From the inner point of view the nerves generally get easily affected by attachments, especially if she is very sensitive. Faith is alright but it helps enormously if one is conscious of the inner difficulty and offers it to Her with a persistent will to change it. Other than that the mind should turn away from the difficulty into something that she finds interesting. Calling peace also will help her. The will to live seems to be diminished too perhaps because of lack of joy in life. However if depression is persisting it will help her to take a course of antidepressants which will give her a vantage point and the time needed for the inner change.
Affectionately,
Alok Da
