Altered states of consciousness can occur from many different
causes. What is commonly considered to be the cause is a chemical
change in the body. This can be from ingesting, or otherwise
introducing a known substance into the body that produces altered
states of consciousness, or by altering the body's chemistry
internally by fasting, sleep deprivation, pain, or meditation.
Altered states of consciousness are very natural and occur to
everyone, though most people do not recognize when it happens to
them. And example would be if you were ever engrossed in some
activity that you lost track of time, and then were surprised when
you realized it. Some people do things like play games, knitting,
working on car, reading, etc. and experience an altered state
without realizing it. That is one reason why video games are so
addicting.
