It may or not have been a neurotic disorder or an actual spiritual experience. Unfortunately, a spiritual experience that is not based on spiritual disciplines can sometimes leave the person literally mad.
Swami Vivekananda says (Complete Works, V2, p 390, available here under the heading Practical Vedanta and Other Lectures, sub-heading The Ideal of a Universal Religion (http://cwsv.belurmath.org/volume_2/vol_2_frame.htm) -
Therefore, there must be some other instrument to take us beyond, and that instrument is called inspiration. So instinct, reason, and inspiration are the three instruments of knowledge. Instinct belongs to animals, reason to man, and inspiration to God-men. But in all human beings are to be found, in a more or less developed condition, the germs of all these three instruments of knowledge. To have these mental instruments evolved, the germs must be there. And this must also be remembered that one instrument is a development of the other, and therefore does not contradict it. It is reason that develops into inspiration, and therefore inspiration does not contradict reason, but fulfils it. Things which reason cannot get at are brought to light by inspiration; and they do not contradict reason. The old man does not contradict the child, but fulfils the child. Therefore you must always bear in mind that the great danger lies in mistaking the lower form of instrument to be the higher. Many times instinct is presented before the world as inspiration, and then come all the spurious claims for the gift of prophecy. A fool or a semi-lunatic thinks that the confusion going on in his brain is inspiration, and he wants men to follow him. The most contradictory irrational nonsense that has been preached in the world is simply the instinctive jargon of confused lunatic brains trying to pass for the language of inspiration.
The first test of true teaching must be, that the teaching should not contradict reason. And you may see that such is the basis of all these Yogas.
And in V4 (http://cwsv.belurmath.org/volume_4/vol_4_frame.htm), heading Lectures and Discourses, sub-heading Concentration, he says:
Universal methods have been organised according to different philosophers. Some say the state we want to attain is superconsciousness of the mind — going beyond the limitations the body has made for us. The value of ethics to the Yogi lies in that it makes the mind pure. The purer the mind, the easier it is to control it. The mind takes every thought that rises and works it out. The grosser the mind, the more difficult [it is] to control [it]. The immoral man will never be able to concentrate his mind to study psychology. He may get a little control as he begins, get a little power of hearing. ... and even those powers will go from him. The difficulty is that if you study closely, you see how [the] extraordinary power arrived at was not attained by regular scientific training. The men who, by the power of magic, control serpents will be killed by serpents. ... The man who attains any extraordinary powers will in the long run succumb to those powers. There are millions [who] receive power through all sorts of ways in India. The vast majority of them die raving lunatics. Quite a number commit suicide, the mind [being] unbalanced.
The study must be put on the safe side: scientific, slow, peaceful. The first requisite is to be moral. Such a man wants the gods to come down, and they will come down and manifest themselves to him. That is our psychology and philosophy in essence, [to be] perfectly moral. Just think what that means! No injury, perfect purity, perfect austerity! These are absolutely necessary. Just think, if a man can attain all these in perfection! What more do you want? If he is free from all enmity towards any being, ... all animals will give up their enmity [in his presence]. The Yogis lay down very strict laws... so that one cannot pass off for a charitable man without; being charitable. ...