It could be partly because of a general disinterest in the mundane life, a phase that many spiritual seekers go through. The things that engaged oneself and drew out the force of life no more excites us. Hence, the life forces remains largely engaged internally, with the nascent or developing inner life. The surface consciousness then has a tendency to fall asleep, as during meditation. The other cause, which is less likely, is loss of vital energy as one begins to open to beings and forces of the occult worlds. But this sleepiness is accompanied by tiredness as well.
Affectionately,
Alok Da
