The phenomenon you're describing is known as the "nocebo effect," which is the opposite of the well-known "placebo effect." While the placebo effect refers to the positive impact that a belief in a treatment or intervention can have on a person's health, the nocebo effect refers to the negative impact that a belief in harmful effects can have on a person's health.
In the context of hearing voices, it is theoretically possible that the fear or belief of hearing voices could lead some individuals to perceive or interpret innocuous sounds or internal mental processes as voices. This doesn't mean that they are experiencing auditory hallucinations in the same way as individuals with certain mental health conditions like schizophrenia, but rather they might be more attuned to normal auditory sensations and interpret them as something abnormal or frightening due to their fears or beliefs.
Phantom pregnancy, or pseudocyesis, is a related phenomenon where a person believes they are pregnant and may exhibit physical symptoms of pregnancy despite not actually being pregnant. In this case, the psychological belief can lead to physical changes and symptoms.
It's important to note that the nocebo effect is a complex psychological phenomenon and not everyone will experience it in the same way. Some people might be more susceptible to the power of suggestion and negative beliefs, while others may not be affected at all.
If someone is experiencing distressing symptoms, including hearing voices or other concerning sensations, it's crucial for them to seek professional help from a qualified mental health professional. A proper evaluation and diagnosis are essential to determine the underlying causes and appropriate treatments, if necessary. Self-diagnosis or relying solely on internet information can lead to misunderstandings and potential exacerbation of symptoms.