Changes of consciousness may be a sign of medical conditions, for example, aneurysm, brain infection, brain tumor or injury, dementia, drug use, epilepsy, heart disease, heatstroke, low blood sugar, poisoning, or shock.

If you think you are experiencing changes in consciousness, talk to your doctor.

• The French philosopher Rene Descartes theorized the idea that while the mind and body are separate, they do interact.
• Structuralists used introspection to analyze and report conscious sensations, thoughts, and experiences of their own minds. It was very subjective but inspired further research.
• American psychologist William James thought consciousness was unbroken and continuous despite the constant changes.
• Psychoanalyst Sigmund Freud focused on understanding the importance of the unconscious and conscious mind.

The study of consciousness does not have a universally accepted operational definition. Modern researchers have proposed two significant theories of consciousness.

• Integrated Information Theory: This approach focus on learning about the physical processes that underlie our conscious experiences. It tends to focus on whether something is conscious and to what degree it is conscious.
• Global Workspace Theory: This theory suggests that we have a memory bank from which the brain draws information to form the experience of conscious awareness.