There are many different types of altered states. They can be light or deep; voluntary or involuntary; physical, emotional, mental or intuitive in origin; beneficial or counterproductive; and include any state of mind from being hyper-aware, hyper-focused or inspired to totally zoning out.
It is not easy for others to tell the difference – or even if a person is in an altered state or not. One clue is that if someone is reading, writing, painting, meditating, listening to music, dancing, watching a film, playing or working with something and does not look up and make eye contact or give other sign of having acknowledged your presence when you walk into the room, that person may be in one altered state or another.
Besides occurring spontaneously, different types of altered states may be induced by things like flickering light (e.g. from TV & computer monitors, fluorescent lights), electromagnetic stimulation of the brain, music, repetitive movements (e.g. rocking back-&-forth), drugs, air-born chemicals, pain, shock, fear, sex, stress, sensory overload, allergic reaction, fatigue, precipitation, deep concentration, meditation, prayer, contemplation and hypnosis.