Schizophrenia is a chronic and severe mental disorder that affects how a person thinks, feels, and behaves. People with schizophrenia may seem like they have lost touch with reality and experience hallucinations, delusions, disorganized thinking and behavior. One of the most common symptoms of schizophrenia is hearing voices that other people do not hear. These auditory hallucinations are a key feature of schizophrenia, occurring in 60-80% of people with the disorder. But where do these voices come from? In this article, we will explore the possible origins of auditory hallucinations in schizophrenia.
What are auditory hallucinations?
Auditory hallucinations, also known as “hearing voices”, refer to hearing speech or other sounds that do not have an external source. The voices heard by people with schizophrenia are perceived as coming from outside their own thoughts. The voices often sound real and distinct from the person’s own inner voice. People with schizophrenia do not have voluntary control over the voices and often cannot stop them or make them go away. The voices may talk directly to the person, carry on conversations, provide a running commentary on the person’s behavior, or issue commands. The voices can range from being neutral to highly negative and disturbing in nature.
Prevalence of auditory hallucinations
Auditory hallucinations are one of the most common symptoms of schizophrenia, occurring in:
– 60-80% of people with schizophrenia
– 10-15% of people with major depressive disorder
– 10-15% of people with bipolar disorder
However, auditory hallucinations can also occur in people without mental illness, especially in times of grief, extreme stress, sleep deprivation, sensory deprivation, or intoxication.
When do auditory hallucinations start?
In people with schizophrenia, auditory hallucinations most often start between the late teens and mid-30s. However, onset can occur later in life as well. The voices usually begin gradually as indistinct murmurings before progressing to louder and clearer speech over time. Most people first experience neutral or even benign voices, which over the course of the illness become more negative, threatening, or harassing in nature. Stress, lack of sleep, and social isolation tend to make the voices worse.
What causes auditory hallucinations?
The exact causes of auditory hallucinations in schizophrenia are still not fully understood, but most experts believe they arise from a complex interplay of factors:
Brain abnormalities
- Differences in brain structure and function have been found in people with schizophrenia who experience auditory hallucinations compared to healthy controls. These include:
- – Reduced grey matter volume in the superior temporal gyrus (auditory processing area)
- – Hyperactivity in brain regions linked to auditory processing when hallucinating
- – Functional connectivity differences between frontal and temporal lobe regions
These abnormalities may make people with schizophrenia more likely to misattribute internal thoughts and memories as coming from an external source.
Neurotransmitter imbalances
- Too much dopamine activity, especially in the limbic system, may contribute to psychotic symptoms like hallucinations.
- Deficits in serotonin and glutamate activity may also play a role.
Stress and trauma
- High levels of stress and trauma are linked to an increased risk of psychosis and auditory hallucinations.
- Childhood adversity and PTSD especially increase the chances of experiencing voices.
Genetics
- Schizophrenia has a genetic component, suggesting auditory hallucinations may partly be inherited.
- However, no single “hallucination gene” has been discovered.
Cognitive biases
- A tendency to misattribute internal thoughts as external voices may be linked to auditory hallucinations.
- Memory and attention deficits common in schizophrenia may also contribute.
So in summary, abnormalities in brain structure and function, neurotransmitter imbalances, high stress, trauma, genetics, and cognitive biases all likely interact in complex ways to produce auditory hallucinations in schizophrenia.
Are the voices “real”?
The voices heard in schizophrenia feel completely real to the person experiencing them. However, these auditory hallucinations do not represent actual perceptions of real voices from the external environment. Instead, they are thought to arise from internal phenomena occurring within the brain itself. Potential origins include:
- Misattributed internal speech – Inner speech or thoughts are mistakenly assigned to an external source
- Dysfunctional memory – Voices arise from memories being incorrectly activated
- Hypervigilance – Excessive sensitivity to sounds leads neutral stimuli to be perceived as voices
- Disordered corollary discharge – Inability to properly monitor internal versus external speech
So while the voices subjectively feel real, they do not actually represent sounds from real people talking. Treatments aim to help patients realize the voices originate within their own minds rather than from external sources.
What do the voices say?
The content of auditory hallucinations in schizophrenia varies greatly between individuals. Some common themes include:
- Neutral voices – Provide a running commentary on the person’s actions/thoughts
- Commanding voices – Issue orders, often unpleasant or demanding
- Conversing voices – Hold conversations with each other or the person
- Abusive/persecutory voices – Insulting, critical, threatening, or harassing
- Non-verbal sounds – Buzzing, hissing, knocking, laughter, crying
The voices sometimes reflect a person’s fears or insecurities. People who have experienced trauma are more likely to hear violent or abusive voices. With illness progression, benign voices often become more hostile and disturbing over time. Gender also influences voice content – women tend to hear more personal voices than men.
Are the voices recognizable?
The identities of the voices vary:
- Strangers – voices sound unfamiliar and anonymous
- Family/friends – voices resemble or claim to be people the person knows
- Famous people – voices sound like celebrities or public figures
- Supernatural entities – voices claim to be from God, the devil, aliens etc.
- Self – voices speak in the first-person or reflect the person’s own thoughts
Most people with schizophrenia report hearing unfamiliar voices. However, some recognize the voices as family members, famous people, or supernatural beings. Hearing one’s own thoughts spoken aloud in the second-person is also common.
How many voices are heard?
The number of distinct voices heard by people with schizophrenia includes:
- Single voice
- Two to five voices
- Large chorus of voices
In one study, the breakdown was:
| One voice | 30% of people |
| Two to five voices | 55% of people |
| Over five voices | 15% of people |
So while multiple voices are most common, a sizable minority of people hear only a single voice. The number of voices may increase throughout the course of the illness as symptoms worsen.
When do voices occur?
Auditory hallucinations can occur at any time, but some patterns emerge:
- When resting or falling asleep
- When waking up
- When alone or in quiet environments
- When stressed, anxious, or sleep-deprived
- When thinking deeply or concentrating
Being in noisy or crowded environments tends to suppress the voices. Keeping occupied also helps minimize occurrences. Times of solitude, idleness, and distress exacerbate voices. Nighttime or early morning are common times to experience voices.
How are voices treated?
Treatment options for auditory hallucinations in schizophrenia include:
Medication
Antipsychotic medications are effective for reducing hallucinations in 60-70% of patients. They work by blocking dopamine and other neurotransmitters linked to psychosis.
Psychotherapy
Talk therapy approaches like cognitive behavioral therapy (CBT) can help patients cope with voices and recognize them as internal phenomena rather than real voices.
Repetitive transcranial magnetic stimulation (rTMS)
rTMS uses magnetic pulses to activate or suppress brain regions involved in hallucinations. It has shown success in reducing voice frequency.
Acceptance and commitment therapy (ACT)
ACT focuses on accepting voices as part of one’s mental experience while living a values-based life. It aims to reduce distress rather than eliminate voices completely.
While not curable, combining medication, therapy, and brain stimulation offers hope for managing auditory hallucinations and improving quality of life for schizophrenia patients.
Conclusion
In summary, auditory hallucinations are a key symptom of schizophrenia, affecting 60-80% of people with the disorder. The voices arise from internal neurological phenomena rather than real external sounds. While no single cause is known, brain abnormalities, neurotransmitter imbalances, genetics, stress, and cognitive biases all appear to interact in complex ways to produce voice-hearing experiences in schizophrenia. Although the voices feel real to the sufferer, treatment can help patients recognize hallucinations as biological symptoms and develop coping strategies to improve their condition.
