Dopaminergic Function in the Psychosis Spectrum: An [18F]-DOPA Imaging Study in Healthy Individuals With Auditory Hallucinations

Howes, Oliver; Shotbolt, Paul; Bloomfield, Michael; Daalman, Kirstin; Demjaha, Arsime; Diederen, Kelly; Ibrahim, Kemal; Kim, Euitae; McGuire, Philip; Kahn, René S.; Sommer, Iris

doi:10.1093/schbul/sbr195

Cited by 80 publications

(87 citation statements)

References 38 publications

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“…63,91 Dopamine levels have a prominent role in models of disorders like schizophrenia and PD, 95 including hallucinations. 96 Overall, there are many similarities in neurotransmitters between sleep-related perceptions and waking hallucinations, although the balance of neurotransmitter levels appears to be different. In REM sleep, sustained and high ACh levels from the forebrain and tegmental nucleus are important, whereas low ACh levels (or possibly transient ACh release) seem to characterize hallucinations.…”

Section: Differences In Brain Functions and Systemsmentioning

confidence: 99%

What Is the Link Between Hallucinations, Dreams, and Hypnagogic–Hypnopompic Experiences?

Waters

Blom²,

Dang‐Vu

et al. 2016

SCHBUL

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By definition, hallucinations occur only in the full waking state. Yet similarities to sleep-related experiences such as hypnagogic and hypnopompic hallucinations, dreams and parasomnias, have been noted since antiquity. These observations have prompted researchers to suggest a common aetiology for these phenomena based on the neurobiology of rapid eye movement (REM) sleep. With our recent understanding of hallucinations in different population groups and at the neurobiological, cognitive and interpersonal levels, it is now possible to draw comparisons between the 2 sets of experiences as never before. In the current article, we make detailed comparisons between sleep-related experiences and hallucinations in Parkinson's disease, schizophrenia and eye disease, at the levels of phenomenology (content, sensory modalities involved, perceptual attributes) and of brain function (brain activations, resting-state networks, neurotransmitter action). Findings show that sleep-related experiences share considerable overlap with hallucinations at the level of subjective descriptions and underlying brain mechanisms. Key differences remain however: (1) Sleep-related perceptions are immersive and largely cut off from reality, whereas hallucinations are discrete and overlaid on veridical perceptions; and (2) Sleep-related perceptions involve only a subset of neural networks implicated in hallucinations, reflecting perceptual signals processed in a functionally and cognitively closed-loop circuit. In summary, both phenomena are non-veridical perceptions that share some phenomenological and neural similarities, but insufficient evidence exists to fully support the notion that the majority of hallucinations depend on REM processes or REM intrusions into waking consciousness.

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Section: Differences In Brain Functions and Systemsmentioning

confidence: 99%

What Is the Link Between Hallucinations, Dreams, and Hypnagogic–Hypnopompic Experiences?

Waters

Blom²,

Dang‐Vu

et al. 2016

SCHBUL

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“…In a separate study, Disorganized traits, in non-clinical adults assessed with the SPQ, were positively correlated with D2 dopamine receptor availability, as measured by SPECT imaging with [123I]IBZM binding, in the right striatum [76]. Lastly, dopamine synthesis capacity in a non-clinical group with subclinical auditory hallucinatory phenomena did not differ from a control group; and schizotypal and other psychosis-spectrum symptoms were not related to dopamine synthesis capacity [77]. …”

Section: Neurobiological Studies: Structural and Neurochemical Findingsmentioning

confidence: 99%

Schizotypal Personality Disorder: A Current Review

Rosell

Futterman

McMaster

et al. 2014

Curr Psychiatry Rep

124

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The study of schizotypal personality disorder (SPD) is important clinically, as it is understudied, challenging to treat, often under-recognized or misdiagnosed, and associated with significant functional impairment. SPD also represents an intermediate schizophrenia-spectrum phenotype, and therefore, can provide a better understanding of the genetics, pathogenesis, and treatment of related psychotic illnesses. In this review we discuss recent findings of SPD related to epidemiology and functional impairment; heritability and genetics; working memory and cognitive impairments; social-affective disturbances; and neurobiology. Additionally, we examine the challenges associated with treating patients with SPD, as well as clinical recommendations. Finally, we address future directions and areas in need of further exploration.

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“…However, little is known about the prevalence, clinical features and pathophysiology of psychosis in the broad SCA population or in particular SCAs. SCA 17 stands out as a hereditary ataxia which typically involves the basal ganglia, is often associated with psychosis, and is often considered a mimic of Huntington’s disease [21, 22, 35]. …”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the dopamine hypothesis of schizophrenia supposes that dysregulation of pre-synaptic dopamine in the striatum underlies the illness and susceptibility to psychosis [23, 24, 25, 26]. Schizophrenia has been associated with increased striatal dopamine synthesis as seen by PET radiotracer studies using 18 fluoro-dihydroxyphenyl-l-alanine (DOPA), an abnormality found to be specific to psychotic disorders compared to non-psychotic depression and other psychiatric disorders lacking psychosis [24, 35, 36]. Dopamine is synthesized from tyrosine through the action of tyrosine hydroxylase (TH), converting tyrosine to DOPA, which then is converted into dopamine [37].…”

Section: Introductionmentioning

confidence: 99%

Psychosis in Spinocerebellar Ataxias: a Case Series and Study of Tyrosine Hydroxylase in Substantia Nigra

et al. 2017

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Spinocerebellar ataxias are a genetically heterogeneous group of degenerative diseases typically characterized by progressive ataxia and to various degrees, neuropathy, amyotrophy, and ocular abnormalities. There is increasing evidence for non-motor manifestations associated with cerebellar syndromes including cognitive and psychiatric features. We studied a retrospective clinical case series of eight subjects with spinocerebellar ataxias (SCAs) 2, 3, 7, and 17, all displaying features of psychosis, and also measured tyrosine hydroxylase (TH) staining of the substantia nigra (SN) at autopsy, among four of the subjects. We hypothesized that increased dopamine production in the SN may underlie the pathophysiology of psychosis in SCAs, given evidence of increased dopamine production in the SN in schizophrenia, as measured by TH staining. We analyzed differences in TH staining between the SCA psychosis cohort (n = 4), a heterogeneous ataxic cohort without psychosis (n = 22), and non-diseased age- and sex-matched control group (n = 12). SCA subjects with psychosis did not differ significantly in TH staining versus ataxic cases without psychosis. There was, however, increased TH staining in the ataxic cohort with and without psychosis (n = 26), compared to non-diseased controls (n = 12). Psychotic features were similar across subjects, with the presence of delusions, paranoia, and auditory hallucinations. Our findings are preliminary because of small numbers of subjects and variable neuropathology; however, they suggest that psychosis is a clinical feature of SCAs and may be under-recognized. While the underlying pathophysiology remains to be fully established, it may be related to extra-cerebellar pathology, including a possible propensity for increased dopamine activity in the SN.

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Dopaminergic Function in the Psychosis Spectrum: An [18F]-DOPA Imaging Study in Healthy Individuals With Auditory Hallucinations

Cited by 80 publications

References 38 publications

What Is the Link Between Hallucinations, Dreams, and Hypnagogic–Hypnopompic Experiences?

What Is the Link Between Hallucinations, Dreams, and Hypnagogic–Hypnopompic Experiences?

Schizotypal Personality Disorder: A Current Review

Psychosis in Spinocerebellar Ataxias: a Case Series and Study of Tyrosine Hydroxylase in Substantia Nigra

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