A team of researchers led by Dr. Tanya Luhrmann of Stanford University explored the various pathways to voice-hearing among clinical and nonclinical populations in a new article in Schizophrenia Bulletin. They propose that while trauma may at times play a major role, it may also play a minor or no role in experiences voice-hearing.
Research has shown that trauma can play a role in increasing risk for voice-hearing. Theorists also suggest the following relationships: trauma can serve as a biological, biopsychosocial, and/or psychological stressor or trigger, trauma can influence the voice content, and trauma-associated dissociation experienced by the individual may create or maintain hallucinations.
The authors of the present study highlight that the method in which trauma is operationalized across studies has varied extensively (e.g., use of various trauma scales or definition of trauma in diagnostic manuals (DSM-IV vs DSM-V). Additionally, there exists an implicit assumption of the existence of a causal pathway between trauma and hallucinations, when in fact trauma is often experienced within the context of various other risk factors such as concussion and brain injuries. While experiences of trauma globally are about 70%, rates of psychosis are less than 1%.
This study sought to explore the various pathways to voice-hearing among clinical and non-clinical populations (excepting experiences due to known etiological factors such as drug use, sensory deprivation, epilepsy, etc.). The authors suggest that trauma can play a major role in some hallucinations, a minor role in many, or no role in other hallucinations.
They write that “there is enough evidence to conclude that trauma is a significant risk factor for psychosis and for voice-hearing in particular. Yet the finding that trauma increases the risk for hallucinations and for psychosis is quite different from the claim that trauma is necessary for either to occur.”
In their review, the study authors make the following points:
Trauma if Often but Not Always Associated With Voice-Hearing in Populations with Psychosis
Here the authors point out that not all persons who report hearing voices report trauma. Some studies have demonstrated that:
- Between 34% and 53% of patients with severe mental illness (SMI) report childhood sexual or physical abuse
- 56% of patients experiencing a first episode of psychosis report childhood sexual abuse
- 47% of persons diagnosed with schizoaffective disorder report childhood sexual abuse
- 38% of inpatient populations with psychosis report having experienced sexual abuse
While not all persons who experience voice-hearing report trauma, studies have demonstrated a relationship between childhood adversity and hallucinations such that early trauma exposure doubled the risk of hallucination. Even though these relationships have been documented, other studies highlight individuals who report childhood abuse but do not report hallucinations. The opposite is also true, that there are some who report hallucinations but do not report childhood abuse.
Voice-hearing is Often Associated with Propensity and Practice in Nonclinical Populations
Many individuals in the general population report experiences of voice-hearing. The authors cite reports of voice hearing in culturally diverse settings where these experiences are highly valued. The Hearing the Voice project of Durham and Yale Universities provides evidence for voice hearing associated with instances of hypnosis, during meditation practices, and among many psychics and spiritualists.
Many of these individuals perceive these voices as a gift, experience control over them, and find these experiences less distressing than clinical populations. The authors emphasize that while trauma cannot be ruled out in these cases, the reports of positive hallucinations suggest other pathways to voice hearing. Interestingly, non-clinical voice-hearers report more positive and controllable experiences when compared to clinical samples.
Trauma is Associated with Different Phenomenologies in Voice-hearing
Here the authors emphasize the differences in experiences of voices. Most notably:
- People with past trauma experienced voices that were louder than normal speech and related to real people in their lives, memories, and involved other sensory modalities.
- 43% of people who reported hearing voices could not identify a specific trigger for the first time they heard a voice.
- In those who could not identify a specific trigger, voices were less severe, less frequent and with more neutral content than those who associate an adverse event with first hearing a voice.
- Those with clear triggers report other hallucinations, poorer mental health, and are more likely to be in contact with a health professional for concerns regarding the voices.
Novel Data on Different Phenomenological Presentations of Voice-hearing
The authors present results of a study in which a 45-second track that represented the experience of hearing voices was played for 11 okomfo (individuals from the Cape Coast, Ghana who are understood to talk with the local gods) and 7 Christians. The results suggest different types of voice hearing experiences.
- Pattern I: “psychosis-like” presentation
- Hear audible positive voices (God or gods) and negative voices (demons).
- Hear various auditory events: e.g. whispering, commanding, murmuring.
- A reported instance when others thought they were psychiatrically impaired.
- Denied childhood trauma.
- Pattern II: “trauma-related dissociation” presentation
- Hear audible positive (God or gods) voices and negative (demons) voices.
- Narrow range of auditory events.
- Less clearly outlined period of psychiatric impairment.
- Clear presentation of experience of violence or trauma.
- Pattern III: “simple trance” presentation
- Attenuated voice-hearing.
- More emphasis on visual hallucinations.
- No period when others thought they were psychiatrically impaired.
- Denied trauma.
- Voice-hearing more novelistic, with rich imaginative detail.
- Pattern IV: “incidental” hallucinations
- Hear voices no more than once/week.
- No account of others believing they were psychiatrically impaired.
- Denied trauma.
- Little evidence of elaborated trance.
- No variety of auditory events.
The authors suggest “when people have experienced trauma and the trauma is salient for them, voice-hearing may be more harsh and more auditorily diverse. They also suggest that there may be pathways to hallucination in which trauma plays little role.”
Two mechanisms for explaining auditory hallucinations not related to trauma are presented: Psychological/cognitive and neurobiological. The authors argue that both of these mechanisms are consistent with observations that learning can change the way voices are experienced and the experience of the voices may be influenced by the social world of the voice-hearer.
The authors conclude that because the relationship between trauma and voice-hearing has been illuminated, alternate pathways to voice-hearing should be explored. The use of ethnographic data is presented as a beneficial method for phenomenological explorations.
Luhrmann, T. M., Alderson-Day, B., Bell, V., Bless, J. J., Corlett, P., Hugdahl, K., … & Peters, E. (2019). Beyond trauma: a multiple pathways approach auditory hallucinations in clinical and nonclinical populations. Schizophrenia Bulletin, 45(Supplement_1), S24-S31. (Link)