Auditory Hallucinations
- Article Author:
- Tanu Thakur
- Article Editor:
- Vikas Gupta
- Updated:
- 10/5/2020 10:03:07 AM
- For CME on this topic:
- Auditory Hallucinations CME
- PubMed Link:
- Auditory Hallucinations
Introduction
Auditory hallucinations are the sensory perceptions of hearing voices without an external stimulus. This symptom is particularly associated with schizophrenia and related psychotic disorders but is not specific to it. Auditory hallucinations are one of the major symptoms of psychosis. Nonpsychotic disorders known to be associated with auditory hallucinations are mood disorders, trauma-related, substance-related, neurological, personality, as well as their occurrence in "healthy" individuals.[1] It is essential to recognize the disorders associated with the symptom of auditory hallucinations to treat the underlying cause. These voices can be distressful when they are threatening, derogatory, commanding, or haunting, affecting the social and occupational functioning of an individual. They can be distressing to families and friends. Even though many individuals attain full remission, a good number live with these harmful voices, thereby sirening for a close follow up with an elaborate interprofessional team with the objective of providing holistic treatment.
Etiology
Auditory hallucinations can present along with a variety of disorders. Firstly, auditory hallucinations are reported to be elicited with major psychiatric disorders that include schizophrenia and other psychotic disorders, affective disorders such as bipolar (manic, mixed, depressed), unipolar depression, personality disorders, post-traumatic stress disorder (PTSD), anorexia, and bulimia nervosa.[2][3] Secondly, they can be seen in substance-induced disorders such as intoxication with stimulants, hallucinogenic drugs, cannabis, and withdrawal from substances such as alcohol. Medication-induced psychosis is another important etiology. Specifically, auditory hallucinations have been reported as adverse effects of medications for attention-deficit hyperkinetic disorder, antimalarials, and antiparkinson drugs.[4][5][4]
Fourthly, medical conditions causing damage to the peripheral sensory pathways such as acquired deafness;[6] endocrine metabolic diseases such as thyroid dysfunction,[7] and nutritional deficiencies such as vitamin D and B12 may present with auditory hallucinations.[2] Chromosomal disorders such as Prader-Willi syndrome, autoimmune disorders,[8] and acquired immunodeficiencies such as HIV/AIDS are other causes of auditory hallucinations.[9] Sleep disorders such as narcolepsy,[10] neurological conditions such as tinnitus, cerebral tumors,[11] traumatic brain injury,[12] epilepsy particularly temporal lobe epilepsy, viral encephalitis, delirium, and cardiovascular events that involve the brainstem regions or areas of temporal, temporoparietal or occipital pathways should also be considered in the differential. Neurodegenerative conditions such as Parkinson's disease and dementia with Lewy bodies can cause auditory hallucinations.[2] Lastly, auditory hallucinations can occur transiently in conditions of extreme physiological and psychological stress such as dissociative identity disorder, fatigue, and bereavement.[13]
Epidemiology
The estimated prevalence of auditory hallucinations in the general population ranges from 5 to 28%.[14] Auditory hallucinations are the most commonly reported in psychotic patients.[15] They are prevalent in 75% of individuals suffering from schizophrenia, 20-50% of individuals with bipolar disorder, 10% of individuals with major psychotic depression, and 40% of individuals with PTSD.[16]
In children and adolescents, the prevalence has been noted to be 9% and ranging between 5 to 16%, respectively.[17][18] In children, it is mostly seen in conjunction with conduct disorder,[19] migraine,[20] and anxiety.[21] The discontinuation rate of auditory hallucinations in adolescence ranges from 3 to 40% each year.[22]
Pathophysiology
The pathophysiology of auditory hallucinations has been explained with suggested hypotheses at various levels, including cultural, clinical, cognitive, cellular, brain imaging, and molecular levels.[23]
MRI findings have demonstrated spontaneous activation of the auditory network, which is the activation of mainly the left superior temporal gyrus, further extending into the superior temporal sulcus and the classic speech perception areas. Hence, this suggests that the activation pattern in a non-hallucinating individual and a hallucinating individual without an external sound source is the same.[24]
Most studies suggest activation of the fronto-temporoparietal network in auditory hallucinations, however, studies are inconclusive regarding the strength and direction of cortical connectivity.[25]
A neurocognitive model called the VOICE model was presented, with the auditory hallucinations being explained to be due to the hyperexcitation of the bottom-up system localized to an auditory-perceptual network in the temporal lobe and hypo-excitation of the top-down system localized to an attention-executive network localized to frontal lobe areas.[26] An auditory hallucination is thought to be the result of hyper-excitation of the bottom-up system, such that neurons in this region spontaneously fire in the absence of a triggering external stimulus, and hypo-excitation of the top-down system, such that attention is not regulated appropriately to an external event and internal events are not correspondingly inhibited or suppressed.
Some data suggest that the thalamus-amygdala pathways are activated, thereby processing an emotional response to the auditory hallucinations,[23] further proved by another study detecting choline and N-acetyl aspirate ratio abnormalities in the thalamus.[27]
At a neurochemical level, the most commonly discussed hypothesis is of the dopamine D2 and serotonin 5HT2a receptor blockade. Neuroimaging studies have demonstrated increased D2 receptor occupancy in the striatal system and 5HT2a receptor occupancy in the caudate nucleus.[28] Magnetic resonance spectroscopy studies suggest a mediating role of glutamate and glutamine in auditory hallucinations.[29]
History and Physical
Auditory hallucinatory experiences are psychopathological end-points. Disturbances in consciousness may occur earlier in the course that includes thought blocking, thought pressure, obsessive perseveration, and failure to discriminate between thought and perception.[30]
In the late prodromal stages, inner speech becomes more objectified and externally perceived.[31]
It is essential to differentiate clinical from non-clinical auditory hallucinations.
Clinical auditory hallucinations:[32]
- Have greater linguistic capacity with a limited vocabulary
- Evoke a greater emotional response
- Have higher frequencies of hallucinations that are correlated with delusion formation
- Have more negative than positive content
- Last for a longer duration
- Are comprised of voices that may build up slowly or wane off gradually, and there is an urge to respond to these voices audibly
- Are considered by patients to be voices that are coming from outside their heads
- Interfere with activities and cognitive functions
Evaluation
The evaluation of auditory hallucinations begins with an interview. The interview consists of a general psychiatric interview that includes the evolution of the symptoms to the current episode, triggering factors, a psychiatric review of systems, past psychiatric diagnosis and treatment, history of substance use with any recent use, family history of possible psychiatric illnesses, social history including history of trauma (physical, mental or sexual abuse). It is essential to remember that the individual's history might have to corroborate with collateral information whenever there is suspicion of a patient's distorted reality.
Secondly, a detailed medical history, including current and past medical diagnoses, current medications being used, including over-the-counter and herbal medications, should be obtained.
A mental status examination would focus on the appearance, behavior, thought content, thought process, insight, and judgment, besides speech, mood, and affect. Describing the auditory hallucinations in terms of location, tone, the number of voices heard would help differentiate it from nonclinical auditory hallucinations.
Lastly, a set of lab findings to identify the cause of auditory hallucinations due to other non-psychiatric conditions may include, but may not be limited to the following:
- Urine toxicology
- Complete blood count with differential
- Vitamin B12 and D levels
- Renal function test
- Serum electrolytes
- Hepatic function test
- Blood alcohol
- Computed tomography (CT) or Magnetic Resonance Imaging (MRI) should be considered if organic brain abnormalities are considered in the differential diagnoses
- EEG for a seizure disorder
Treatment / Management
Pharmacotherapy
- The mainstay of the pharmacological treatment of auditory hallucinations is the use of antipsychotics. Although they have limited individual clinical efficacy, they make auditory hallucinations bearable.[32] Sometimes, they can be efficacious in stopping the auditory hallucinations by the use of a single antipsychotic, and sometimes a second antipsychotic is needed in conjunction to resolve auditory hallucinations and other symptoms of psychosis.
- Clozapine has been shown to effective in 30 to 60% of individuals with intractable auditory hallucinations. Clozapine does not totally stop the auditory hallucinations always, but abates them to a significant degree and helps in dealing with them in a number of patients.[32]
- Treatment of patients with schizophrenia with two atypical antipsychotics over the course of 4 to 6 weeks with no clinical response indicates treatment-resistant schizophrenia. Auditory hallucinations may persist in these patients.
- For such patients, it is advised to use one of the following antipsychotics if they have not been tried before-clozapine 300 to 900 mg/day, risperidone 4 to 6 mg/day, olanzapine 10 to 20 mg/day, quetiapine 300 to 600 mg/day or aripiprazole 15 to 30 mg/day.
- Mood enhancers may help individuals to cope with the auditory hallucinations better.[32]
Psychotherapy
Cognitive Behavioral Therapy (CBT)
- CBT is aimed at emotional and behavioral changes, teaches to modify the auditory hallucinations experiences, and teaches a sense of control over them to improve the overall functioning of an individual.
- CBT uses Socratic interviewing rather than confrontation.[33]
- Reality testing and behavioral experiments are the ideas behind CBT.
- It can be provided in an individual or group format with supplemental self-help resources made available.
Other treatment approaches include ACT (acceptance and commitment therapy), HIT (hallucination focused integrative treatment), ATT (metacognitive therapy attention training technique), relating therapy, distraction techniques, and HVN (hearing voices network) self-help group, all strategies to cope better with the voices.
Emerging treatments
Several studies have shown efficacy in reducing auditory hallucinations using transcranial magnetic stimulation but have no firm evidence.[34]
Differential Diagnosis
To differentiate the causes of auditory hallucinations it is pertinent to focus on the following:
- Age of onset- unlike other non-psychotic disorders, schizophrenia has an age of onset in late adolescence and is rarely seen as a bimodal distribution in women during late adolescence and in their 40's.
- Genetic factors- family history of the psychotic disorder has been shown to be associated to have a genetic linkage.
- Presentation- a history of substance use may indicate a substance-induced psychotic disorder, preexisting medical conditions, and their treatments, past or current neurological abnormalities, and individuals with a history of seizures can shed light on the cause of auditory hallucinations.
Prognosis
The symptom of auditory hallucinations in schizophrenia is considered to be a poor prognostic factor in schizophrenia, with 50% of individuals on antipsychotics attaining full remission, 25% hearing voices occasionally, and 25% being resistant to treatment.[35]
Other poor prognostic factors adding to poor treatment response include early age of onset, male gender, and multiple inpatient hospitalizations.
Complications
Auditory hallucinations can place an individual at imminent risk of harm to self or can be at risk of harm to others if they act on commanding or derogatory voices.
Individuals may lack insight and judgment and may have to be hospitalized involuntarily. Care needs to be taken to build trust and respect with the patients for maintaining regular follow up even after discharge from hospitals given a notable high chance of relapse due to non-compliance with medications and appointments.
Moreover, medications have their own short-term and long-term adverse effects that include extrapyramidal symptoms noted with antipsychotics such as dystonia, tremors, tardive dyskinesia, parkinsonism, and metabolic syndrome.
Deterrence and Patient Education
Patients and their families need to be educated regarding the significance of compliance with medications. Many patients are unable to adhere to medications, lost to follow up, and end up relapsing and being hospitalized, creating a cycle of events. Severely sick patients should be assigned to an assertive community treatment program while providing treatment, rehabilitation, and support services. Other support groups focus on destigmatizing mental illness for the family and the individual. Involving individuals in vocational and art therapy can improve self-esteem and help integrate with their functioning.
Lastly, educating patients about case management services can assist them in providing coordination between psychiatrists and social workers, keeping up with the appointments, making home visits, and accompanying patients when needed.
Enhancing Healthcare Team Outcomes
There are some limitations in the understanding and strategies within the healthcare system towards auditory hallucinations. Firstly, defining auditory hallucinations, understanding clinical auditory hallucinations, and providing support are essential. Next, recognizing the gravity of the complications of auditory hallucinations that would require hospitalization could prevent suicide and homicide events.
While a detailed history and mental status examination are paramount, identifying the cause of auditory hallucinations allows the right selection of the management strategies. Antipsychotics are the treatment of choice, although their efficacy might vary on an individual basis. Despite the clear cut strategies, it is important to understand that auditory hallucinations are a sensory perception that will require patience and involvement by an interprofessional team to see results. Hence it is important to raise awareness and education in the inpatient and outpatient staff, customize discharge plans according to the individual with self-management strategies and communicate discharge plans, safety tools with caregivers, and case managers.
The outcome of auditory hallucinations depends upon the coordination and the promptness of each caregiver during the care process.