Modular-Level Functional Connectome Alterations in Individuals With Hallucinations Across the Psychosis Continuum

Functional Connectivity Between Auditory and Medial Temporal Lobe Networks in Antipsychotic-Naïve Patients With First-Episode Schizophrenia Predicts the Effects of Dopamine Antagonism on Auditory Verbal Hallucinations

Background

Understanding how antipsychotic medication ameliorates auditory verbal hallucinations (AVHs) through modulation of brain circuitry is pivotal for understanding the pathophysiology of psychosis and for predicting treatment response.

Methods

This case-control study included examinations at baseline and at follow-up after 6 weeks. Initially, antipsychotic-naïve patients with first-episode schizophrenia who were experiencing AVHs were recruited together with healthy control participants. Antipsychotic treatment with the relatively selective D2 receptor antagonist amisulpride was administered as monotherapy. Functional connectivity measured by resting-state functional magnetic resonance imaging between networks of interest was used to study the effects of D2 blockade on brain circuitry and predict clinical treatment response. Hallucinations were rated with the Positive and Negative Syndrome Scale.

Results

Thirty-two patients experiencing AVHs and 34 healthy control participants were scanned at baseline. Twenty-two patients and 34 healthy control participants were rescanned at follow-up. Connectivity between the auditory network and the medial temporal lobe network was increased in patients at baseline (p = .002) and normalized within 6 weeks of D2 blockade (p = .018). At baseline, the connectivity between these networks was positively correlated with ratings of hallucinations (t = 2.67, p = .013). Moreover, baseline connectivity between the auditory network and the medial temporal lobe network predicted reduction in hallucinations (t = 2.34, p = .032).

Conclusions

Functional connectivity between the auditory network and the medial temporal lobe predicted response to initial antipsychotic treatment. These findings demonstrate that connectivity between networks involved in auditory processing, internal monitoring, and memory is associated with the clinical effect of dopamine antagonism.

The whole-brain connectome landscape in patients with schizophrenia: a systematic review and meta-analysis of graph theoretical characteristics

The alterations of connectome in schizophrenia have been reported, but the results remain inconsistent. We conducted a systematic review and random-effects meta-analysis on structural or functional connectome MRI studies comparing global graph theoretical characteristics between schizophrenia and healthy controls. Meta-regression and subgroup analyses were performed to examine confounding effects. Based on the included 48 studies, Structural connectome in schizophrenia showed a significant decrease in segregation (lower clustering coefficient and local efficiency, Hedge's g= -0.352 and -0.864, respectively) and integration (higher characteristic path length and lower global efficiency, Hedge's g= 0.532 and -0.577 respectively). The functional connectome showed no difference between groups except γ. Moderator analysis indicated that clinical and methodological factors exerted a potential effect on the graph theoretical characteristics. Our analysis revealed a weaker small-worldization trend in structural connectome of schizophrenia. For the relatively unchanged functional connectome, more homogenous and high-quality studies are warranted to elucidate whether the change was blurred by heterogeneity or the presentation of pathophysiological reconfiguration.

Psychotic-like experiences as a co-occurring psychopathological indicator of multi-dimensional affective symptoms: Findings from a cross-sectional survey among college students

BACKGROUND

Although connections between psychotic-like experiences (PLEs) and a series of non-psychotic disorders have been widely explored in previous research, it is unclear whether PLEs could act as a co-occurring psychopathological indicator of multi-dimensional affective symptoms.

METHODS

A total of 4761 students took part in an online survey which assessed the frequency of PLEs and three types of affective symptoms over lifetime. Binary logistic regression models were used to examine associations between PLEs and each type of affective symptom. Network analysis was conducted to explore the relationship among three subtypes of PLEs - persecutory ideation (PI), bizarre experiences (BEs) and perceptual abnormalities (PAs), and different types of affective symptoms.

RESULTS

The results showed that compared with the non-PLEs group, the PLEs group suffered significantly higher risk of experiencing three types of affective symptoms, including manic symptoms [adjusted odds ratio (aOR) 11.50, 95 % confidence interval (CI) (4.59-28.81)], depressive symptoms [aOR 7.28, 95 % CI (4.98-10.66)] and anxiety symptoms [aOR 4.47, 95 % CI (3.10-6.43)]. In the network model, bizarre experiences were the most critical central symptom. Both depressive and anxiety symptoms were most strongly associated with persecutory ideation while manic symptoms were most closely related to bizarre experiences.

LIMITATIONS

Cross-sectional data and self-reported symptoms.

CONCLUSIONS

These findings suggest that PLEs are a vital co-occurring indicator of multi-dimensional affective symptoms and show its enormous potential as a target for a host of mental health problems. Further investigation may shed light on the aetiology of the relationship between different subtypes of PLEs and affective symptoms.