Differences in the internal structure of hallucinatory experiences between clinical and nonclinical populations

Time varying dynamics of hallucinations in clinical and non-clinical voice-hearers

Auditory verbal hallucinations (AVH) are frequently associated with psychotic disorders, yet also occur in non-clinical voice-hearers. AVH in this group are similar to those within clinical voice-hearers in terms of several phenomenological aspects, but non-clinical voice-hearers report to have more control over their AVH and attribute less emotional valence to them. These dissimilarities may stem from differences on the neurobiological level, as it is still under debate whether the mechanisms involved in AVH are the same in clinical and non-clinical voice-hearers. In this study, 21 clinical and 21 non-clinical voice-hearers indicated the onset and offsets of AVH during an fMRI scan. Using a method called leading eigenvector dynamics analysis (LEiDA), we examined time-varying dynamics of functional connectivity involved in AVH with a sub-second temporal resolution. We assessed differences between groups, and between hallucination and rest periods in dwell time, switching frequency, probability of occurrence, and transition probabilities of nine recurrent states of functional connectivity with a permutation ANOVA. Deviations in dwell times, switching frequencies, and switch probabilities in the hallucination period indicated more erratic dynamics during this condition regardless of their clinical status. Post-hoc analyses of the dwell times exhibited the most distinct differences between the rest and hallucination condition for the non-clinical sample, suggesting stronger differences between the two conditions in this group. Overall, these findings suggest that the neurobiological mechanisms involved in AVH are similar in clinical and non-clinical individuals.

A data-driven linguistic characterization of hallucinated voices in clinical and non-clinical voice-hearers

BACKGROUND

Auditory verbal hallucinations (AVHs) are heterogeneous regarding phenomenology and etiology. This has led to the proposal of AVHs subtypes. Distinguishing AVHs subtypes can inform AVHs neurocognitive models and also have implications for clinical practice. A scarcely studied source of heterogeneity relates to the AVHs linguistic characteristics. Therefore, in this study we investigate whether linguistic features distinguish AVHs subtypes, and whether linguistic AVH-subtypes are associated with phenomenology and voice-hearers' clinical status.

METHODS

Twenty-one clinical and nineteen non-clinical voice-hearers participated in this study. Participants were instructed to repeat verbatim their AVHs just after experiencing them. AVH-repetitions were audio-recorded and transcribed. AVHs phenomenology was assessed using the Auditory Hallucinations Rating Scale of the Psychotic Symptom Rating Scales. Hierarchical clustering analyses without a priori group dichotomization were performed using quantitative measures of sixteen linguistic features to distinguish sets of AVHs.

RESULTS

A two-AVHs-cluster solution best partitioned the data. AVHs-clusters significantly differed in linguistic features (p < .001); AVHs phenomenology (p < .001); and distribution of clinical voice-hearers (p < .001). The "expanded-AVHs" cluster was characterized by more determiners, more prepositions, longer utterances (all p < .01), and mainly contained non-clinical voice-hearers. The "compact-AVHs" cluster had fewer determiners and prepositions, shorter utterances (all p < .01), more negative content, higher degree of negativity (both p < .05), and predominantly came from clinical voice-hearers.

DISCUSSION

Two voice-speech clusters were recognized, differing in syntactic-grammatical complexity and negative phenomenology. Our results suggest clinical voice-hearers often hear negative, "compact-voices", understandable under Broca's right hemisphere homologue and memory-based mechanisms. Conversely, non-clinical voice-hearers experience "expanded-voices", better accounted by inner speech AVHs models.

Association of schizophrenia polygenic risk score with data-driven cognitive subtypes: A six-year longitudinal study in patients, siblings and controls

Cross-sectional studies have shown that the polygenic risk score for schizophrenia (PRS_SCZ) may influence heterogeneity in cognitive performance although evidence from family-based longitudinal study is limited. This study aimed to identify trajectories of cognitive function and assess whether the PRS_SCZ is associated with baseline cognitive performance and predicted six-year trajectories. We included 1119 patients with a schizophrenia spectrum disorder, and 1059 unaffected siblings and 586 unrelated controls who are eligible at baseline. Genotype data were collected at baseline, whereas clinical and sociodemographic data were collected at baseline, three and six years. Group-based trajectory modeling was applied on a weighted standardized composite score of general cognition to unravel cognitive subtypes and explore trajectories over time. We followed a standard procedure to calculate the polygenic risk score. A random-effects ordinal regression model was used to investigate the association between PRS_SCZ and cognitive subtypes. Five cognitive subtypes with variable trajectories were found in patients, four in siblings and controls, and six in all combined samples. PRS_SCZ significantly predicted poor cognitive trajectories in patients, siblings and all samples. After Bonferroni correction and adjustment for non-genetic factors, only the results in all combined sample remained significant. Cognitive impairment in schizophrenia is heterogeneous and may be linked with high PRS_SCZ. Our finding confirmed at least in all combined samples the presence of genetic overlap between schizophrenia and cognitive function and can give insight into the mechanisms of cognitive deficits.

A systematic review and narrative synthesis of data-driven studies in schizophrenia symptoms and cognitive deficits

To tackle the phenotypic heterogeneity of schizophrenia, data-driven methods are often applied to identify subtypes of its symptoms and cognitive deficits. However, a systematic review on this topic is lacking. The objective of this review was to summarize the evidence obtained from longitudinal and cross-sectional data-driven studies in positive and negative symptoms and cognitive deficits in patients with schizophrenia spectrum disorders, their unaffected siblings and healthy controls or individuals from general population. Additionally, we aimed to highlight methodological gaps across studies and point out future directions to optimize the translatability of evidence from data-driven studies. A systematic review was performed through searching PsycINFO, PubMed, PsycTESTS, PsycARTICLES, SCOPUS, EMBASE and Web of Science electronic databases. Both longitudinal and cross-sectional studies published from 2008 to 2019, which reported at least two statistically derived clusters or trajectories were included. Two reviewers independently screened and extracted the data. In this review, 53 studies (19 longitudinal and 34 cross-sectional) that conducted among 17,822 patients, 8729 unaffected siblings and 5520 controls or general population were included. Most longitudinal studies found four trajectories that characterized by stability, progressive deterioration, relapsing and progressive amelioration of symptoms and cognitive function. Cross-sectional studies commonly identified three clusters with low, intermediate (mixed) and high psychotic symptoms and cognitive profiles. Moreover, identified subgroups were predicted by numerous genetic, sociodemographic and clinical factors. Our findings indicate that schizophrenia symptoms and cognitive deficits are heterogeneous, although methodological limitations across studies are observed. Identified clusters and trajectories along with their predictors may be used to base the implementation of personalized treatment and develop a risk prediction model for high-risk individuals with prodromal symptoms.

Differences between self-reported and clinician-rated evaluations of 1-year changes in auditory verbal hallucinations among schizophrenia patients

Auditory verbal hallucinations (AVHs) constitute a frequent and distressing symptom of schizophrenia, associated with physical, emotional, and cognitive challenges. Despite their clinical importance, changes in the multiple dimensions of AVHs during treatment have rarely been examined, and subjective views thereof have received minimal attention. Here, we evaluated 87 patients with schizophrenia-related AVHs using the Hamilton Program for Schizophrenia Voices Questionnaire (HPSVQ; a self-report questionnaire) and the Psychotic Symptom Rating Scales-Auditory Hallucination Subscale (PSYRATS-AH; a clinician-rated scale) at baseline and after 6 months and 1 year of treatment. We explored dimensions that changed from the perspectives of both clinicians and patients and the relationships between these perceptions over the year. The test-retest reliabilities of the HPSVQ and PSYRATS-AH were generally fair. Improvements in AVHs were evident over the first 6 months; the PSYRATS-AH revealed a broader range of symptom improvement than did the HPSVQ. The "interference with life" dimension on the HPSVQ was not reduced, but the "disruption to life" score on the PSYRATS-AH was. At both baseline and 6 months, the physical characteristics of AVHs (frequency, duration, and loudness) were significantly correlated with both distress and life interference/disruption; all correlations except that for frequency were reduced at 1 year. The clinician-rated and self-reported personal perspectives on AVHs exhibited both differences and similarities; physical AVH components and subjective distressful experiences changed in different ways in those with chronic, persistent AVHs. The HPSVQ and PSYRATS-AH data were complementary, improving our understanding of the clinical implications of AVHs and subjective patient distress.

Prevalence of psychotic symptoms among older adults in an Asian population

BACKGROUND

Psychotic symptoms are common among older adults and are seen in a wide range of conditions. Most studies examining the prevalence and correlates of psychotic symptoms among older adults have been conducted in Western populations. To address this gap the current study was undertaken to establish the prevalence and correlates of psychotic symptoms and paranoid ideation within a community sample of older adults without dementia in an Asian population.

METHODS

The Well-being of the Singapore Elderly (WiSE) study was a comprehensive single phase, cross-sectional survey. All respondents were assessed using the Geriatric Mental State examination (GMS). Specific questions of the GMS were then used to establish the prevalence of hallucinations and persecutory delusions.

RESULTS

A total of 2,565 respondents completed the study giving a response rate of 65.6%. The prevalence of any psychotic symptoms in this population of older adults was 5.2%. The odds of hallucinations and any psychotic symptoms were significantly higher among those of Malay ethnicity, and those who had no formal education. Older adults aged 75-84 years were significantly associated with lower odds of having hallucinations (vs. older adult aged 60-74 years), while homemaker status was significantly associated with lower odds of having any psychotic symptoms.

CONCLUSIONS

The prevalence of psychotic symptoms among older Asian adults without dementia was higher than that reported from Western countries. Psychotic symptoms were associated with Malay ethnicity, poor cognitive performance and fewer years of schooling, visual and hearing impairment as well as depression and irritability.