Hallucinations can involve your hearing, sight, sense of smell, taste, or touch. Based on this categorization, there are five main types of hallucinations, such as auditory, visual, olfactory, gustatory, and tactile hallucinations. This article will focus on auditory hallucinations to give you a better understanding of what this term means. 

What are auditory hallucinations?

The most common type of hallucination is auditory in nature. While auditory hallucinations are common symptoms of schizophrenia and bipolar disorder, 10 to 15 percent of the healthy general population also experience them from time to time. While some people with auditory hallucinations hear voices in their head, others may hear different sounds or noises. 
The voice you hear in your head could sound like someone is talking to you or telling you to take specific actions. The voice may be kind, hostile, or indifferent. 
Adults are not the only ones affected by auditory hallucinations. Studies show that they are relatively common among pre-pubertal children at psychiatric clinics as well. One study aimed to describe auditory hallucinations in children and establish links with DSM IV (fourth edition of the Diagnostic and Statistical Manual of Mental Disorders) diagnoses.

What causes auditory hallucinations?

Mental health conditions
Mental health issues, such as schizophrenia, are among the most common causes of auditory hallucinations. Schizophrenia is a severe mental illness that affects how you think, feel, and behave. If you have schizophrenia, you may feel like you have lost touch with reality. Hearing voices is one of the hallmark symptoms of psychotic disorders and schizophrenia. The voices can originate from inside your head or outside. Some voices may be argumentative, others simply telling you what to do. Hallucinations can occur with other mental illnesses as well, such as bipolar disorder, major depressive disorder, post-traumatic stress disorder, borderline personality disorder, and more. 

Infections and fevers 
Some infections can trigger auditory hallucinations and make you hear things. An example of one such infection is meningitis. Very high fevers can have similar effects, causing disorientation and hallucinations. While hallucinating while running a fever is not dangerous, it can certainly be scary. 
Those experiencing fever-induced hallucinations typically report seeing images or hearing sounds that aren't real. Treating the cause of the illness will likely resolve the hallucinations. 
Parkinson's disease
Parkinson's disease is a neurodegenerative disorder with motor and nonmotor symptoms characterizing the disease. Psychosis is a common characteristic of Parkinson's disease. Parkinson's Disease Psychosis (PDP) includes various hallucinations - visual and nonvisual - and delusions. Anyone suffering from PDP can testify how detrimental it can be to life quality. Although visual hallucinations are more common among PDP sufferers, voice-hearing can also occur. 
Dementia and Alzheimer's disease 
People suffering from dementia or delirium frequently experience auditory or visual hallucinations. If you or your loved one has Alzheimer's, hallucinations are more likely to happen during the later stages. Some people even talk back to the voices they hear because they seem so real. With Lewy body dementia, visual hallucinations are much more prevalent. 

Alcoholic hallucinosis is a rare complication of chronic alcohol abuse. A period of heavy alcohol consumption generally triggers such episodes that are predominantly auditory in nature. If you were a heavy drinker for many years, you can see or hear things that are not there even after quitting. 
Illegal hallucinogenic drugs
Like ecstasy and LSD, certain street drugs can make you see and hear things that aren't real. Such false perceptions - whether visual, auditory, or other - can happen not only during drug use but even after quitting. LSD (d-lysergic acid diethylamide) is a potent mood-altering chemical known to create incorrect sensory perceptions. PCP (phencyclidine) - developed in the 1950s - is another example of hallucinogenic drugs. PCP was initially used as an intravenous anesthetic; it has since been discontinued due to serious adverse effects. Using these or similar drugs can result in hallucinating, seeing things, or hearing voices. 
Sleep-related hallucination is called parasomnia. Although parasomnia events are primarily visual, they can also involve other senses, including your hearing. Parasomnia episodes typically happen when you are about to fall asleep or just waking up. Sleep deprivation and a chronic lack of sleep can also be at the root of sleep-induced hallucinating.
Prescription medications
In addition to mental health problems, illegal drugs, and sleep, certain medications can also be associated with hallucinations. While all medications have side effects, some have more severe adverse effects, including antipsychotic drugs. Prescription drugs for psychosis, epilepsy, and depression are well known for causing hallucinations. 
Migraine-sufferers often complain about seeing things or hearing sounds and voices. Studies have shown that hallucinating patients also suffer from depression, in addition to migraines. Researchers are still not entirely sure why the rates of hallucination go up among depressive migraine sufferers. 
Thyroid Conditions
Many different thyroid disorders exist, but only one, in particular, has been associated with hearing voices. Myxedema is a rare condition where the thyroid hormone levels get dangerously low and make you hear things.
Simply put, tinnitus is ringing in the ears. Although the name implies a ringing sound, what you may hear may be similar to hissing, roaring, clicking, or buzzing. The sound could be loud, or soft, low or high pitched. Tinnitus can affect one ear only or both ears. Tinnitus is more common than you may think. According to estimates, about 10 percent of adults in the United States experiences tinnitus each year. 
Although ringing in the ear is not considered a hallucination, suffering from tinnitus can raise your risk of becoming a voice-hearer. Additionally, if you also suffer from depression, your chances of experiencing hallucinations go even higher. 
Hearing loss
If you suffer from hearing loss, you may hear sounds, music, or voices that are not actually there. Studies show that auditory hallucinations are prevalent among patients with hearing impairment. The more severe your hearing loss, the worse the hallucinations get. Although researchers do not fully understand all the factors potentially contributing to this phenomenon, your doctor should evaluate your symptoms, as they may be treatable.
Epilepsy is a disorder with the hallmark symptom of recurrent seizures unprovoked by any stimuli. When the repeated attacks from epilepsy affect the part of the brain that processes hearing, you might begin hearing buzzing sounds or voices. Recurring seizures can also distort how you hear things, making sounds less loud or clear. 
Musical hallucination (MH)
Musical hallucination or musical tinnitus is hearing music that no one else can hear. Tinnitus - a ringing sound in the ear - is quite common and generally involves a simple sound such as a buzzing or ringing. However, these perceptions can be far more complex for some people, where they can hear music that is not being played. Although anyone can experience this type of hallucination, it is far more common among women than men and those over 60 years of age. If you live alone or have hearing loss, you are more likely to experience it.

How to diagnose auditory hallucinations? 

How your doctor will treat auditory hallucinations will depend on the cause of your particular symptoms. To find the reason for the voices you hear, your doctor will take your health history and ask many questions to understand your case better. He will want to know the type of sounds and voices you hear, when your symptoms started, and the list of medications and other substances you take.
Your physician may refer you to a psychologist to rule out or confirm any mental illness or order other tests to identify the reason for the hallucinations. Hearing exams will likely be one of the first tests ordered to see if hearing voices is a consequence of hearing impairment. Another potential test is an electroencephalogram (EEG) to look for epilepsy.

How to treat auditory hallucinations? 

As you can see, multiple possible reasons exist that may cause your hallucinations. Diagnosis and treatment, therefore, can be quite complicated. It does not mean that there is no hope. Doctors can often successfully identify the cause, and put together a treatment plan that helps the voice-hearing episodes either disappear entirely or happen less frequently.
At times, resolving your auditory hallucinations is very simple. If the voices are caused by antipsychotic medications, changing the dose of your medicine may help. If, however, a psychotic disorder is to blame for what you experience, a combination of medication and therapy may be necessary.