There are 4 states of consciousness attained through Mantra Yoga. Here they are:
Relaxed and concentrated state of mind
Due to withdrawal from the material thoughts, distractions, focusing of mind only on Mantra, the mind is relaxed and becomes concentrated. Research shows the presence of alpha wave/rhythm of the brain.
Rotation of consciousness around Mantra
Awareness is revolved around the mantra, its pronunciation, yantra (psychic shape) and it’s meaning, which builds up psychic energy which can then be used for spiritual purposes.
Sakshi Bhav: the state of being a mere witness
The attitude of an unconcerned observer, this particular attitude is very important as it allows bypassing or witnessing disturbances arising in the conscious & subconscious mind. Thoughts are generally very difficult to negotiate, this approach of “Sakshi Bhav” allows to overcome this problem.
Lost awareness of the outside world
When a practitioner goes deep into the meditation states while chanting mantra, there is absolutely no awareness about happenings in the surrounding environment.
Only Mantra awareness remains
Even there is no self, the mantra & its awareness is present when a practitioner reaches higher states.