There is a growing recognition in psychosis research of the importance of hallucinations in modalities other than the auditory. This has focused attention on cognitive and neural processes that might be shared by, and which might contribute distinctly to, hallucinations in different modalities. In this article, I address some issues around the modality-generality of cognitive and neural processes in hallucinations, including the role of perceptual and reality-monitoring systems, top-down and bottom-up processes in relation to the psychological and neural substrates of hallucinations, and the phenomenon of simultaneous multimodal hallucinations of the same entity. I suggest that a functional systems approach, inspired by some neglected aspects of the writings of A. R. Luria, can help us to understand patterns of hallucinatory experience across modalities and across clinical and non-clinical groups. Understanding the interplay between modality-general and modality-specific processes may bear fruit for improved diagnosis and therapeutic approaches to dealing with distressing hallucinations.

Background: A previous study (Gauntlett-Gilbert and Kuipers, 2005) has suggested that distress associated with complex visual hallucinations (CVHs) in younger adults with psychosis may more strongly relate to appraisals of meaning than to the content of the hallucination. However, visual hallucinations are most commonly seen in the disorders of later life, where this relationship has not been investigated. Aim: To establish if there is a relationship between appraisals of CVHs and distress in older, non-psychotic people with CVHs. Method: All variables were measured using a semi-structured interview and were compared between a high distress group (n = 16) and a low distress group (n = 19). Results: The high distress group rated their hallucinations as more malevolent and omnipotent, with greater negative implications for physical and mental health. There was no significant difference between groups on ratings of hallucination content (independently rated), frequency, awareness or control. Conclusion: Appraisals of CVHs are linked to distress.

Background: Distressing visual hallucinations (VH) are frequently present in schizophrenia. Despite their prevalence, limited research exists regarding effective clinical interventions. Cognitive models of VH state that distress results from threat appraisals of the hallucination. Method: This individual case study describes the use of a graded exposure approach following the discovery of phobic anxiety associated with visual hallucinatory content. Treatment involved 20 sessions of individual cognitive behaviour therapy (CBT), of which 12 sessions focused on graded exposure. Results: A reduction in frequency of visions and associated distress was reported and these changes were maintained at a 3-month follow-up. Conclusions: The findings are consistent with the cognitive model of VH. Through exposure to the hallucinatory content, the client re-appraised her VH as non-threatening, and her fear of them reduced. This reduction in anxiety led to a decrease in the occurrence of the VH.

Three cases of schizophrenia (DSM-III-R) (l), whilst responding to treatment, exhibit a group of symptoms which had the essential features of “flashbacks”, as described in relation to psychedelic drugs, though there was no evidence of psychedelic drug misuse. Symptoms were characterised by memory flashes of the original psychotic experience, followed immediately by very brief re-experiencing of earlier symptoms, including visual perceptual changes in clear consciousness and full insight. Symptoms were less clear, less severe, but more distressing, than the original episodes. Symptoms were triggered by stress/anxiety, and relieved by an anxiolytic. The association of flashbacks with schizophrenia is discussed.