Auditory hallucinations have a wide range of causes, from psychiatric conditions like schizophrenia to hearing loss, medication side effects, and even the ordinary transition between waking and sleep. About 7.3% of the general population reports experiencing an auditory hallucination at least once in their lifetime, meaning this is far more common than most people realize, and it does not always signal a serious mental illness.
What Happens in the Brain
During an auditory hallucination, the brain’s hearing centers become active without any external sound triggering them. Functional imaging studies show hyperactivity in the auditory cortex, the part of the brain that processes sound, along with disrupted connections between that region and the prefrontal cortex, which helps distinguish real perceptions from internally generated ones. In simple terms, the brain produces a signal that feels identical to hearing an actual sound, and the systems that would normally flag it as “not real” fail to do so.
Dopamine, one of the brain’s main chemical messengers, plays a central role. Excess dopamine activity can make the brain over-interpret random neural signals as meaningful sounds or voices. This is why many medications that reduce hallucinations work by dialing down dopamine signaling. Disruptions in glutamate, another signaling chemical involved in learning and perception, also appear to contribute.
Psychiatric Conditions
Schizophrenia is the condition most strongly associated with auditory hallucinations. In a large study of nearly 5,000 hospitalized patients, 61% of those with schizophrenia were experiencing hallucinations at admission, and auditory hallucinations were the most common type. These often take the form of voices: sometimes a single voice commenting on the person’s actions, sometimes multiple voices conversing, and sometimes “command” hallucinations that instruct the person to do something. People with schizophrenia frequently describe the voices as coming from outside their own head, and the experience can feel completely indistinguishable from a real conversation.
Bipolar disorder and major depression can also produce auditory hallucinations, though less frequently. In the same study, hallucinations were present in about 23% of people admitted during a mixed bipolar episode, 11% during mania, and roughly 10% during a bipolar depressive episode. Unipolar depression had the lowest rate at about 6%. The hallucinations in mood disorders tend to be less severe and more often visual compared with schizophrenia, but voices do occur, particularly when the episode is intense.
Hearing Loss and Sensory Deprivation
One of the lesser-known causes is hearing loss itself. When the ears send less sound information to the brain, the auditory cortex can start generating its own signals to compensate for the missing input. This is sometimes called the deafferentation model: reduced sensory input lowers the brain’s threshold for detecting signals, and spontaneous activity in the auditory system gets interpreted as real sound. A large cross-sectional study found that 16% of people with hearing impairment have experienced auditory hallucinations, including hearing voices. Among those with severe hearing loss, the figure rises to 24%.
What makes these hallucinations distinct is that the person typically has no delusions or disordered thinking alongside them, and they usually recognize that the sounds aren’t real. Musical hallucinations, where a person hears songs or melodies with no external source, are especially common in older adults with significant hearing loss. These are not a sign of psychosis, and they’re often manageable once the hearing loss is addressed with aids or other interventions.
Neurological Conditions
A number of brain and nervous system conditions can trigger auditory hallucinations. Temporal lobe epilepsy is one of the more well-documented causes. Seizure activity in the temporal lobe, which houses the brain’s primary auditory processing areas, can produce sounds, music, or voices during or just before a seizure. Brain tumors or lesions in the temporal lobe, brainstem, or thalamus can do the same by disrupting normal signaling in those regions.
Other neurological triggers include traumatic brain injury, stroke (particularly strokes affecting the brainstem or temporal areas), Parkinson’s disease, viral encephalitis, migraines, and neurodegenerative diseases like dementia. Delirium, a state of acute confusion often seen in hospitalized or critically ill patients, is another common cause. In all of these cases, the hallucinations are a downstream effect of physical changes in the brain rather than a primary psychiatric condition.
Medications and Substances
A surprisingly long list of medications can trigger auditory hallucinations as a side effect. Antidepressants are among the most commonly implicated, accounting for about 18.5% of drug-induced cases in one review. Anti-Parkinson drugs, opioids, ketamine, and the antifungal voriconazole each accounted for roughly 11% of cases. Benzodiazepines, certain antibiotics, vasodilators, corticosteroids, and even aspirin have all been documented as triggers in isolated cases.
Opioids appear to cause hallucinations partly through their effect on dopamine pathways, the same system implicated in schizophrenia. Recreational drugs, particularly stimulants like methamphetamine and cocaine, are well-known triggers. Stimulant psychosis can produce vivid, persistent auditory hallucinations that closely mimic schizophrenia. Alcohol withdrawal is another classic cause: during severe withdrawal (delirium tremens), the brain rebounds from chronic suppression into a hyperexcitable state, which can produce voices, sounds, and other hallucinations.
Sleep-Related Hallucinations
If you’ve ever heard someone call your name just as you were drifting off, or heard a loud bang that jolted you awake, you’ve likely experienced a sleep-related hallucination. Hypnagogic hallucinations happen as you fall asleep, and hypnopompic hallucinations happen as you wake up. Between 8% and 34% of these are auditory, involving sounds, voices, words, or environmental noises. They’re typically brief, lasting only a few seconds, which distinguishes them from dreams that have a narrative arc.
These are extremely common and, on their own, completely benign. Sleep deprivation, irregular sleep schedules, stress, and caffeine can all make them more frequent. Narcolepsy also increases their frequency significantly. The key distinction is that these occur only at sleep-wake transitions. Hallucinations that happen during full wakefulness point toward a different cause.
Other Contributing Factors
Several less obvious medical conditions round out the list. Thyroid dysfunction, nutritional deficiencies (particularly B12 and folate), autoimmune disorders, and tinnitus can all produce or contribute to auditory hallucinations. Tinnitus itself, the perception of ringing or buzzing without an external source, is technically a form of auditory hallucination, though it’s rarely classified that way in everyday conversation.
Extreme stress, grief, and social isolation can also trigger hallucinations in otherwise healthy people. Hearing the voice of a recently deceased loved one is surprisingly common during bereavement and is generally considered a normal part of the grieving process rather than a symptom of illness. Prolonged solitary confinement and sensory deprivation can produce hallucinations through a mechanism similar to hearing loss: the brain, starved of external input, begins generating its own.
How Causes Are Identified
Because so many different conditions can produce auditory hallucinations, figuring out the underlying cause requires a broad evaluation. This typically involves a thorough medical history, a review of all current medications and substances, hearing tests, and often brain imaging to rule out tumors, lesions, or stroke. An EEG may be used if epilepsy is suspected. Blood work can identify thyroid problems, nutritional deficiencies, infections, or autoimmune markers.
The context of the hallucinations matters enormously. Voices that come with paranoid beliefs and disorganized thinking point toward a psychotic disorder. Musical hallucinations in an older adult with poor hearing suggest the deafferentation mechanism. Hallucinations that started shortly after a new medication was prescribed raise suspicion of a drug side effect. The hallucination itself is a symptom, not a diagnosis, and the same experience can stem from vastly different underlying causes.