Thursday, 7 July 2016

Voices and Thoughts in Psychosis


In this post, Sam Wilkinson (below right) introduces a forthcoming Special Issue of the Review of Philosophy and Psychology, that he co-edited with psychologist Ben Alderson-Day (below left), on “Voices and Thoughts in Psychosis”.  




If we experience thoughts in our head, how can they seem to not be our own? To understand this, we need to explore what thoughts are and how we know them in the first place. In his paper (“Thinking, Inner Speech, and Self-awareness”) Johannes Roessler outlines two views about knowledge of our own thoughts, attributed to Gilbert Ryle. The first is that we are “alive to” our own thoughts in the “serial process” of thinking, and the second is that we can “eavesdrop” on our inner speech, and interpret our own utterances in much the same was as we interpret the utterances of others. Roessler suggests that the former account is the one that is relevant for understanding thought insertion. 

In her paper (“On Thought Insertion”) Rachel Gunn questions the orthodox accounts of thought that posit ownership without agency. These accounts are not going into enough detail about the different things that “ownership” can mean. She clarifies this using detailed and varied first-person accounts, and presents her own account of thought insertion.

Whereas Gunn focuses on thought insertion as an experience, Pablo Lopez-Silva (“Schizophrenia and the Place of Egodystonic States in the Aetiology of Thought Insertion”) focuses on thought insertion as a delusional belief. For him, the content of the inserted thought is of crucial explanatory relevance. Thought insertion is not simply the product of a low-level disruption to phenomenology, according to which any old thought, in principle, could be experienced as inserted. More specifically, the inserted thought is ego-dystonic, and the delusion serves the function of protecting the subject from that thought. Lopez-Silva argues that we must pay more attention to the role that affective disturbances play in driving and generating ego-dystonic thought contents. 

Such disturbances play a key role in the tradition of phenomenological psychopathology, within which the paper by Peter Handest and colleagues firmly falls. In their paper (“From Thoughts to Voices: Understanding the Development of Auditory Hallucinations in Schizophrenia”) they offer an introduction to the work of Klosterkotter, Conrad, Sass, and Parnas on how a range of disruptions to thoughts and perceptions can develop into auditory hallucinations in the context of schizophrenia. 

Then two papers seek to bridge the gap between AVH and thought insertion: one focusing on phenomenology, the other, on neuropsychology. In the first (“The Spectra of Soundless Voices and Audible Thoughts: Towards an Integrative Model of Auditory Verbal Hallucinations and Thought Insertion”) Clara Humpston & Matthew Broome use first-person accounts to emphasise the phenomenological continuity between experiences of voices and thoughts in psychosis. They reject the idea that thought insertion should primarily be considered a delusion (contra, e.g. Lopez-Silva) and place it on a quasi-perceptual continuum with soundless voices and auditory hallucinations. 
 
Johanna Badcock (“A Neuropsychological Approach to Auditory Verbal Hallucinations and Thought Insertion Grounded in Normal Voice Perception”) shows how a combined account of AVH and thought insertion might be accommodated in a neuropsychological model. Neuroimaging evidence from ordinary voice perception suggests that multiple processing streams are responsible for recognising voice identity, location and other features. Badcock uses these findings to propose that both AVH and TI result from disruptions to neural networks responsible for audition and language, but that their phenomenology will vary depending on which specific network components are affected.

Finally, there are papers in the issue pertaining to orthodox accounts of AVH that view the phenomenon as misattributed inner speech. Daniel Gregory (“Inner Speech, Imagined Speech and Auditory Verbal Hallucinations”) argues that we can make more sense of AVH as misattributed imagined speech (or auditory verbal imagery), rather than inner speech. In turn, inner speech has more in common with actual speech than with verbal imagery.

In contrast, Peter Langland-Hassan (“Hearing a Voice as One’s Own: Two Views of Inner Speech Self-Monitoring Deficits in Schizophrenia”) offers a defence of a revised inner speech model. Key to self-monitoring accounts is the idea that sensory cortex is typically dampened in response to self-generated stimuli. Langland-Hassan extends this account to incorporate thought insertion and thought disorder, with reference to semantic errors in Wernicke’s aphasia. Langland-Hassan uses this example of semantic self-monitoring failure to highlight how the interactions between speech production and perception lie not just in prediction of sensory consequences, but also in the expression of content.

All papers from the issue are currently available on the Review of Philosophy and Psychology website, under “Online First”.



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