Hearing voices that others do not hear is often considered a symptom of mental illness. The American Psychological Association defines an auditory hallucination as “the perception of sound in the absence of an auditory stimulus.” When these hallucinations involve voices, they are called verbal hallucinations.

The word "hallucination" derives from the Latin hallucinatio, meaning "a wandering of the mind." This word first appeared in a 16th-century book titled De Humani Corporis Fabrica, and its earliest English usage occurred In 1572 when the Swiss writer Johann Lavater applied the term to strange noises, omens, and apparitions. Originally, this appellation was applied only when referring to abnormal phenomena, but with time it became associated with any unshared experience and with mental illness.

Today, many people associate hearing voices with mental illness, and it is easy to understand why. Approximately 75 percent of people diagnosed with schizophrenia hear verbal hallucinations. These voices can also be a symptom of post-traumatic stress disorder, bipolar disorder, depression, and anxiety.

The mechanism by which verbal hallucinations manifest is unknown, but possible explanations include biochemical, cognitive, and neurobiological processes.

Studies performed at Murray State University and in the Netherlands found many people who hear voices are not mentally ill.

Furthermore, countless mentally healthy people hear voices. The Greek philosopher Socrates heard a voice throughout his life that warned him not to do certain things that were not to his advantage. Socrates called his voice to daimonion or “the divine.”

Once, while walking with a group of friends, Socrates’s daimon advised him to turn around and take a different road. He called to his friends who had gone ahead, but they ignored him and continued their journey. As his friends proceeded, they were knocked down by a herd of pigs while Socrates remained unscathed.

Nobel Peace Prize winner Martin Luther King, Jr. heard a voice he believed originated from God. During the Montgomery bus boycott, King feared for his life after he received numerous death threats. Despite the danger, King........

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