Functional network interactions in patients with schizophrenia with persistent auditory verbal hallucinations: A multimodal MRI fusion approach using three-way pICA

Altered intrinsic neural activity and its molecular analyses in first-episode schizophrenia with auditory verbal hallucinations

Background

Auditory verbal hallucinations (AVHs) are one of the signature positive symptoms of schizophrenia, affecting a substantial portion of patients with schizophrenia. These hallucinations seriously impact the lives of patients, resulting in a substantial social burden. Recent studies have shown a significant correlation between abnormal local brain activity and the neurobiological mechanisms of AVHs. However, it is not fully clear whether altered intrinsic brain activity in schizophrenia patients with AVHs is correlated with specific neurotransmitter systems.

Methods

We included 50 first-episode, drug-naïve schizophrenia patients with AVHs, 50 patients without AVHs (NAVHs), and 50 age- and sex-matched healthy controls (HCs). The amplitude of low-frequency fluctuation (ALFF) was utilized to explore the altered intrinsic brain activity in the AVH group. Subsequently, we spatially correlated the altered ALFF with neurotransmitter maps using JuSpace.

Results

In our study, compared to HCs, the AVH group exhibited significantly reduced ALFF in multiple brain regions, mainly including the left precuneus, bilateral supplementary motor areas, bilateral paracentral lobules, bilateral precentral gyri, and bilateral postcentral gyri. The NAVH group showed significantly reduced ALFF in the left inferior occipital gyrus, left calcarine gyrus, and left lingual gyrus compared to HCs. Furthermore, the AVH group showed higher ALFF in the right inferior frontal gyrus compared to the NAVH group. Additionally, these ALFF alterations in the AVH group were closely related to three neurotransmitters, including dopamine, serotonin and norepinephrine.

Conclusion

We link neurotransmitters to abnormal intrinsic brain activity in first-episode, drug-naïve schizophrenia patients with AVHs, contributing to a comprehensive understanding of the pathophysiological processes and treatment pathways underlying AVHs.

[Spatiotemporal psychopathology-German version of the Scale for Space and Time Experience in Psychosis (STEP) : A validated measurement instrument for the assessment of spatial and temporal experience in psychotic disorders]

Historical authors (e.g., Ludwig Binswanger and Eugène Minkowski) postulated that the experience of patients with schizophrenia is characterized by time fragmentation. From a clinical perspective, patients with schizophrenia also suffer from difficulties in spatial perception (e.g., abnormalities in the experience of interpersonal distance and spatial orientation). Although these changes can lead to a serious detachment from reality, to considerable suffering of the affected persons and to difficulties in the therapeutic process, the abnormal experience of space and time in psychotic disorders has not yet been sufficiently investigated. One possible reason is the lack of appropriate and standardized instruments that quantify the experience of space and time in patients with psychotic disorders. Based on an innovative concept, the so-called spatiotemporal psychopathology (STPP), a clinical rating scale for the systematic-quantitative assessment of spatial and temporal experience in patients with psychotic disorders was developed. This article presents the German version of the Scale for Space and Time Experience in Psychosis (STEP). The original English version of the STEP measures different spatial (14 phenomena) and temporal (11 phenomena) phenomena in 25 items. The STEP shows both a high internal consistency (Cronbach's alpha = 0.94) and a significant correlation with the Positive and Negative Syndrome Scale (PANSS; p < 0.001). In summary, the German version of the STEP scale presented here represents an important instrument in the German-speaking countries for the assessment of spatial and temporal experience in patients with psychotic disorders.