Associations between delusion proneness and personality structure in non-clinical participants: comparison between young and elderly samples

[Doomsday delusions of religious content (apocalyptic version)]

OBJECTIVE

To define psychopathological and phenomenological characteristics of the apocalyptic variant of end-world delusion with religious content (EWDRC) in schizophrenia, to identify features of clinical dynamics of delusional disorders and their interaction with delusional behavior of patients.

MATERIAL AND METHODS

A total of 28 patients with schizophrenia (F20.01, F20.02 according to ICD-10) and EWDRC were examined. Clinical-psychopathological and follow-up methods were used.

RESULTS

The development of the end-world delusional ideas occurred in unstructured affective-delusional disorder with acute sensual delusion. Two types of EWDRC were differentiated: with predominance of perception delusion or picturesque delusion. These types differed by acuity and massiveness of psychotic symptomatology, the mono- or polythematic character of delusional disorders, affect type, as well as by the duration and intensity of the development of delusional stages, and in their phenomenological specifics.

CONCLUSION

Delusional ideas of the end of the world in schizophrenic patients develop in the structure of the syndrome of acute sensory delusions with a predominance of delusions of perception (type I) or visual-figurative delusions of the imagination (type II), which have different duration, degree of dominance and depth of psychopathological disorders.

Psychological distress associated with the COVID-19 pandemic and suppression measures during the first wave in Belgium

BACKGROUND

The COVID-19 pandemic and subsequent suppression measures have had health and social implications for billions of individuals. The aim of this paper is to investigate the risk of psychological distress associated with the COVID-19 pandemic and suppression measures during the early days of the lockdown. We compared the level of psychological distress at the beginning of that period with a pre-pandemic health survey and assessed the psychological effects of exposure to the COVID-19 pandemic and changes in social activity and support.

METHODS

An online survey was distributed to the general population in Belgium 3 days after the beginning of the lockdown. 20,792 respondents participated. The psychological distress of the population was measured using the GHQ-12 scale. Social activities and support were assessed using the Social Participation Measure, the Short Loneliness Scale, and the Oslo Social Support Scale. An index of subjective exposure to the COVID-19 pandemic was constructed, as well as a measure of change in occupational status. Measurements were compared to a representative sample of individuals extracted from the Belgian Health Interview Survey of 2018. Bootstrapping was performed and analyses were reweighted to match the Belgian population in order to control for survey selection bias.

RESULTS

Half of the respondents reported psychological distress in the early days of the lockdown. A longer period of confinement was associated with higher risk of distress. Women and younger age groups were more at risk than men and older age groups, as were respondents who had been exposed to COVID-19. Changes in occupational status and a decrease in social activity and support also increased the risk of psychological distress. Comparing the results with those of the 2018 Belgian Health Interview shows that the early period of the lockdown corresponded to a 2.3-fold increase in psychological distress (95% CI: 2.16-2.45).

CONCLUSIONS

Psychological distress is associated with the consequences of the COVID-19 pandemic and suppression measures. The association is measurable from the very earliest days of confinement and it affected specific at-risk groups. Authorities should consider ways of limiting the effect of confinement on the mental and social health of the population and developing strategies to mitigate the adverse consequences of suppression measures.

The intentionality bias in schizotypy: a social matter

INTRODUCTION

We aimed to investigate the association between schizotypy and intentionality bias, the tendency to interpret ambiguous actions as being intentional, for social and non-social actions separately. This bias contributes to interpersonal difficulties, and has been associated with psychotic symptoms, such as delusions. However, results have been inconsistent for an association between putative psychosis proneness, schizotypy, and intentionality bias. Further, the multidimensional nature of schizotypy has not been considered. Agreeableness was measured to examine the specificity of the relationship, and inhibition to examine its potential role as a mediator.

METHODS

Two online studies are reported (n = 280 and n = 163) in which participants made intentionality judgements about ambiguous actions described in sentences. They also completed questionnaire measures of schizotypy and agreeableness, and inhibitory efficiency (a sentence completion task).

RESULTS

Schizotypy was associated with perceiving ambiguous actions as intentional, particularly in social contexts, after controlling for agreeableness. The association with social intentionality was stronger for schizotypy subscales capturing paranoia and unusual beliefs. Inhibitory efficiency as not a significant predictor of intentionality bias.

CONCLUSION

These finding suggest intentionality biases for social and non-social events are distinguishable. In relation to schizotypy, social situations appear to generate perceptions of intentionality. Intentionality bias represents a phenotypic cognitive risk for psychosis which should be further investigated.

Neuroticism-Withdrawal and Neuroticism-Volatility Differently Influence the Risk of Neuropsychiatric Symptoms in Alzheimer's Disease

BACKGROUND

Neuroticism is recognized as the personality domain that is most strongly associated with behavioral and psychological symptoms (BPS) of Alzheimer's disease (AD). Two sub-components of neuroticism have been recently isolated. Neuroticism-withdrawal (N-withdrawal) refers to the tendency to internalize negative emotion, whereas neuroticism-volatility (N-volatility) reflect the predisposition to externalize negative emotions.

OBJECTIVE

The objective of the current study was to investigate the specific influence of these two sub-components of neuroticism on BPS.

METHODS

One hundred eighty-seven patients with prodromal or mild AD were drawn from the PACO study (Personalité Alzheimer COmportement). Neuroticism and its facets were assessed at baseline using the NEO-PI-R inventory. N-withdrawal and N-volatility were isolated using a principal component analysis led on the six facets composing neuroticism. BPS were measured with the short version of Neuropsychiatric Inventory (NPI-Q) and collected at baseline, then every 6 months over an 18-month follow-up. Linear mixed-effect analyses were conducted to investigate the association between N-withdrawal, N-volatility, and the severity of BPS over the follow-up.

RESULTS

Mean age of the participant was 79.2±6.5; 59% were female; mean MMSE was 24.5±2.5. Both N-volatility and N-withdrawal were related with the NPI-Q (p < 0.001; p = 0,004). N-withdrawal was positively associated with anxiety (p = 0.001) and depression (p = 0.002), while N-volatility was positively related to delusions (p = 0.004), agitation/aggression (p < 0.001), irritability/volatility (p = 0.037), and apathy (p = 0.021).

CONCLUSION

The present study demonstrates that N-volatility and N-withdrawal influence the risk of developing BPS in a different way. These results highlight the relevance of considering sub-components of neuroticism when studying links between personality and BPS.

A possible key role of vision in the development of schizophrenia

Based on a brief overview of the various aspects of schizophrenia reported by numerous studies, here we hypothesize that schizophrenia may originate (and in part be performed) from visual areas. In other words, it seems that a normal visual system or at least an evanescent visual perception may be an essential prerequisite for the development of schizophrenia as well as of various types of hallucinations. Our study focuses on auditory and visual hallucinations, as they are the most prominent features of schizophrenic hallucinations (and also the most studied types of hallucinations). Here, we evaluate the possible key role of the visual system in the development of schizophrenia.

How many bereaved people hallucinate about their loved one? A systematic review and meta-analysis of bereavement hallucinations

BACKGROUND

Bereavement hallucinations (BHs) entail a perception of a deceased in any sense modality or as a quasi-sensory sense of presence. BHs are an associated feature of the proposed Persistent Complex Bereavement Disorder (PCBD) in DSM-5. The goals of this review are to estimate the prevalence of BHs, identify possible moderators, and review the methodological status of this research field.

METHODS

A systematic literature search was conducted through the databases PubMed, PsycINFO, and CINAHL. Studies systematically assessing the prevalence of BHs of a relative or friend were included.

RESULTS

Twenty-one eligible studies were identified and 8 meta-analyses of BHs in different sense modalities were conducted. The prevalence of having one or more BHs was estimated to be 56.6% (95% CI 49.9-63.2), and the estimated prevalence of BHs in specific sense modalities ranged within 7.0-39.7%. Meta-regression analyses revealed associations to age and conjugal bereavement, but results are tentative and dependent on the type of BH in question.

LIMITATIONS

The included studies were methodologically heterogeneous. Limitations included the lack of a valid measure of BHs and low sample generalizability.

CONCLUSION

This first systematic review and meta-analysis of BHs suggests that more than half of the bereaved people experience some kind of BH. However, there are considerable methodological limitations in the research of BHs, which is of pertinent interest as BHs have been linked to the development of a future diagnosis of clinically impairing grief. A valid measure of BHs needs to be developed and used in high-quality epidemiological research using population-based designs.

Hallucinations in schizophrenia and Parkinson's disease: an analysis of sensory modalities involved and the repercussion on patients

Hallucinations have been described in various clinical populations, but they are neither disorder nor disease specific. In schizophrenia patients, hallucinations are hallmark symptoms and auditory ones are described as the more frequent. In Parkinson's disease, the descriptions of hallucination modalities are sparse, but the hallucinations do tend to have less negative consequences. Our study aims to explore the phenomenology of hallucinations in both hallucinating schizophrenia patients and Parkinson's disease patients using the Psycho-Sensory hAllucinations Scale (PSAS). The main objective is to describe the phenomena of these clinical symptoms in those two specific populations. Each hallucinatory sensory modality significantly differed between Parkinson's disease and schizophrenia patients. Auditory, olfactory/gustatory and cœnesthetic hallucinations were more frequent in schizophrenia than visual hallucinations. The guardian angel item, usually not explored in schizophrenia, was described by 46% of these patients. The combination of auditory and visual hallucinations was the most frequent for both Parkinson's disease and schizophrenia. The repercussion index summing characteristics of each hallucination (frequency, duration, negative aspects, conviction, impact, control and sound intensity) was always higher for schizophrenia. A broader view including widespread characteristics and interdisciplinary works must be encouraged to better understand the complexity of the process involved in hallucinations.

The prevalence and characteristics of hallucinations, delusions and minor phenomena in a non-demented population sample aged 60 years and over

OBJECTIVE

Psychotic phenomena can occur in non-clinical subjects. The goals of this study were to assess the prevalence of delusions, hallucinations and minor 'psychotic' phenomena (visual illusions, feeling of presence and passage hallucinations) and to describe the characteristics of the latter in a non-clinical older population.

METHODS

Three hundred and thirteen individuals aged 60 years and older, without cognitive deficits (according to mini-mental state examination scores) or patent psychotic disease, answered a structured questionnaire focusing on delusions, hallucinations and minor phenomena that they had experienced in the previous month. The study sample was stratified by age and gender according to French demographic characteristics.

RESULTS

Twenty per cent of participants reported one or more psychotic phenomena. These subjects did not differ from those without psychotic symptoms as regards their age, mini-mental state examination scores or education. Minor phenomena were the most common (13%). Hallucinations, in any sensory modality, occurred in 9% of participants. No verbal auditory hallucinations or delusions were reported. The prevalence of minor phenomena increased with age and was associated with the use of psychoactive drugs.

CONCLUSION

By extending the spectrum of psychotic symptoms to minor phenomena, we found that psychotic symptoms were common in a non-clinical older population. Whether the increasing prevalence of minor phenomena with age is due to prodromal neurodegenerative disease or to other factors remains to be investigated. Copyright © 2016 John Wiley & Sons, Ltd.

The relationship between temperament and character and subclinical psychotic-like experiences in healthy adults

BACKGROUND

Considerable data support phenomenological and temporal continuity between psychotic disorders and subclinical psychotic-like experiences (PLE's). Although numerous studies have found similar personality correlates for schizophrenia and schizotypal personality disorder patients, their unaffected first-degree relatives, and healthy adults characterized for schizotypal traits, no study has yet investigated personality correlates of PLE's measured by the Community Assessment of Psychic Experiences (CAPE). Our study sought to examine personality correlates of PLE's using the CAPE in healthy adults.

METHOD

The CAPE and temperament and character inventory (TCI) were administered to 415 healthy adults. Regressions examined links between TCI traits and overall PLE levels as well as positive and negative PLE's separately.

RESULTS

Consistent with past studies, lower self-directedness (SD) and reward dependence (RD) and higher self-transcendence (ST) and harm avoidance (HA) significantly predicted overall PLE levels. Higher ST and persistence (P) and lower SD significantly predicted higher levels of positive PLE's while lower SD and RD and higher HA, ST, and cooperativeness (C) predicted higher levels of negative PLE's.

CONCLUSIONS

Associations between TCI and PLE's using the CAPE are strikingly similar to past work in non-clinical and patient samples and provide additional support for phenomenological continuity between psychotic disorders and sub-syndromal psychotic symptoms.

A comprehensive review of auditory verbal hallucinations: lifetime prevalence, correlates and mechanisms in healthy and clinical individuals

Over the years, the prevalence of auditory verbal hallucinations (AVHs) have been documented across the lifespan in varied contexts, and with a range of potential long-term outcomes. Initially the emphasis focused on whether AVHs conferred risk for psychosis. However, recent research has identified significant differences in the presentation and outcomes of AVH in patients compared to those in non-clinical populations. For this reason, it has been suggested that auditory hallucinations are an entity by themselves and not necessarily indicative of transition along the psychosis continuum. This review will examine the presentation of auditory hallucinations across the life span, as well as in various clinical groups. The stages described include childhood, adolescence, adult non-clinical populations, hypnagogic/hypnopompic experiences, high schizotypal traits, schizophrenia, substance induced AVH, AVH in epilepsy, and AVH in the elderly. In children, need for care depends upon whether the child associates the voice with negative beliefs, appraisals and other symptoms of psychosis. This theme appears to carry right through to healthy voice hearers in adulthood, in which a negative impact of the voice usually only exists if the individual has negative experiences as a result of their voice(s). This includes features of the voices such as the negative content, frequency, and emotional valence as well as anxiety and depression, independently or caused by voices presence. It seems possible that the mechanisms which maintain AVH in non-clinical populations are different from those which are behind AVH presentations in psychotic illness. For example, the existence of maladaptive coping strategies in patient populations is one significant difference between clinical and non-clinical groups which is associated with a need for care. Whether or not these mechanisms start out the same and have differential trajectories is not yet evidenced. Future research needs to focus on the comparison of underlying factors and mechanisms that lead to the onset of AVH in both patient and non-clinical populations.

Increased stress reactivity: a mechanism specifically associated with the positive symptoms of psychotic disorder

BACKGROUND

An increased reactivity to stress in the context of daily life is suggested to be an independent risk factor underlying the positive symptoms of psychotic disorder. The aim of this study was to investigate whether positive symptoms moderate the association between everyday stressful events and negative affect (NA), known as stress reactivity. This hypothesis was put to the test in patients with a diagnosis of psychotic disorder. Method The Comprehensive Assessment of Symptoms and History (CASH) and the Positive and Negative Syndrome Scale (PANSS) were used to assess positive and negative symptoms. The experience sampling method (ESM), a structured diary technique, was used to measure stress reactivity and psychotic symptoms in daily life.

RESULTS

Higher levels of positive symptoms (CASH: B = 0.14, p = 0.005; PANSS: B = 0.05, p = 0.000; ESM: B = 0.03, p = 0.000) and lower levels of negative symptoms (PANSS: B = - 0.05, p = 0.001) significantly moderate the association between unpleasant events and NA. No significant moderating effect was found for CASH negative symptoms. Moreover, the moderating effect of lifetime and current symptoms on the stress-NA association was significantly larger for those patients with predominantly positive symptoms (CASH: B = 0.09, p = 0.000; PANSS: B = 0.08, p = 0.000; ESM: B = 0.13, p = 0.000).

CONCLUSIONS

Patients with a 'psychotic syndrome' with high levels of positive symptoms and low levels of negative symptoms show increased reactivity to stress in daily life, indicating that stress reactivity is a possible risk factor underlying this syndrome.

Emotional awareness, gender, and peculiar body-related beliefs

Research has broadly established that emotional disturbances are associated with body image disturbances. This is the first study to examine links between facets of emotional awareness and peculiar body-related beliefs (PBB), or beliefs about an imagined or slight defect in one's appearance or bodily functioning. In a sample of college students (n=216), we found that low emotional clarity (the extent to which the type and source of emotions are understood) was associated with higher PBB in both women and men, and the relation between emotional clarity and PBB was further moderated by attention to emotions (the extent to which emotions are attended to) and gender. Men with low attention to emotions and women with high attention to emotions both experienced higher levels of PBB if they also reported low levels of emotional clarity. This interactive effect was not attributable to shared variance with body mass index, neuroticism or affect intensity.

The psychometric properties of the Peters et al. delusions inventory (PDI) in Taiwan: reliability, validity, and utility

PURPOSE

The Peters et al. Delusions Inventory (PDI) is a commonly used instrument to measure delusion proneness in the general population and includes dimensions that measure distress, preoccupation, and conviction of unusual beliefs. This self-report scale has already been translated into several languages. However, there has not been a validated Taiwanese version previously reported. The aims of the present study were to translate and test the cross-cultural reliability and validity of the PDI in Taiwanese as well as to establish its sensitivity, specificity, and discriminative validity.

METHODS

We administered the questionnaire to a consecutive sample of 253 participants with (n = 154; clinical group including schizophrenia and affective psychosis) or without psychotic disorders (n = 99; non-clinical group). In addition to the Taiwanese version of the PDI (PDI-T), the Taiwanese version of the Brief Psychiatric Symptom Rating Scale (BSRS) was used to measure the severity of psychopathology. We tested the psychometric properties of the PDI-T, including its construct validity, internal consistency, test-retest reliability, concurrent, and discriminative validity.

RESULTS

Overall, the PDI-T showed good construct validity, internal consistency, and stability over time, and it was significantly correlated with the BSRS subscales of psychotic symptoms. The convergent and discriminative validity was satisfactory. The area under the receiver operating characteristic curve of the PDI-T was 0.752. This research found that the most appropriate PDI-T yes/no cut-off scores for determining the absence and presence of delusion proneness were 5 and 13.

CONCLUSIONS

The PDI is a reliable and valid instrument for measuring the dimensionality of delusion proneness and appears to complement subclinical psychosis assessment scales for both epidemiological and clinical research in Taiwan.

Self-reported psychotic symptoms in the general population: correlates in an Iranian urban area

BACKGROUND

Psychosis exists in the community as a continuum of severity. Here, we examine the correlates of self-reported psychotic symptoms in an urban catchment area of Iran.

SAMPLING AND METHODS

Two thousand one hundred and fifty-eight participants (age 18-65 years) residing in southern Tehran (the capital city of Iran) were interviewed using the psychoticism and paranoia dimensions of the Symptom Checklist-90-Revised (SCL-90-R) to assess the severity of psychotic symptoms. Other dimensions of the SCL-90-R assessing nonpsychotic symptoms and a sociodemographic questionnaire were also used. Paykel's Interview for Recent Life Events was used to assess stressful life events.

RESULTS

Independent associations were observed between younger age, female gender, stressful life events and dimensions of depression, anxiety, hostility, obsessive-compulsive symptoms and interpersonal sensitivity and psychoticism. Independent associations were also observed for marital problems, unemployment, stressful life events and dimensions of depression, anxiety, hostility, interpersonal sensitivity and phobic anxiety with paranoid ideation. There was also a trend toward an association between higher educational levels and the severity of psychotic symptoms, particularly paranoid ideation.

CONCLUSIONS

Most of the previously accepted correlations for psychotic symptoms in the community were replicated. An unexpected association between paranoia and female gender, and a trend toward higher rates of psychotic symptoms in more educated participants, were in contrast with the studies in developed settings. The insufficient coverage of psychosis-relevant questions from the SCL-90-R for the entire psychotic diagnostic spectrum should be considered a limitation.

Subclinical delusional ideation and appreciation of sample size and heterogeneity in statistical judgment

Previous studies demonstrate that people high in delusional ideation exhibit a data-gathering bias on inductive reasoning tasks. The current study set out to investigate the factors that may underpin such a bias by examining healthy individuals, classified as either high or low scorers on the Peters et al. Delusions Inventory (PDI). More specifically, whether high PDI scorers have a relatively poor appreciation of sample size and heterogeneity when making statistical judgments. In Expt 1, high PDI scorers made higher probability estimates when generalizing from a sample of 1 with regard to the heterogeneous human property of obesity. In Expt 2, this effect was replicated and was also observed in relation to the heterogeneous property of aggression. The findings suggest that delusion-prone individuals are less appreciative of the importance of sample size when making statistical judgments about heterogeneous properties; this may underpin the data gathering bias observed in previous studies. There was some support for the hypothesis that threatening material would exacerbate high PDI scorers' indifference to sample size.

A preliminary investigation on the relationship between color-word Stroop task performance and delusion-proneness in nonpsychiatric adults

The current study examined whether there is a relationship between the dimension of delusion-proneness and performance on the color-word Stroop task. As dysfunction in the anterior cingulate cortex (ACC) has been related to both Stroop task performance and the presence of delusions in various psychiatric populations, we hypothesized that impaired Stroop performance would relate to increased delusion-proneness in a nonpsychiatric sample. A total of 36 college students, representing a wide range of scores on a measure of delusion-proneness (Peters et al. Delusions Inventory-PDI-21), completed a computerized version of the classic color-word Stroop task. Results revealed a statistically significant positive correlation between the PDI-21 score and the Stroop effect. The pattern of results suggests that reduced efficiency of Stroop performance is related to increasing levels of delusion-proneness. This study appears to be the first to report this relationship across a continuum of delusion-proneness in a nonpsychiatric sample. This finding contributes to the cognitive neurobiological understanding of delusions and adds further support for the dimensional construct of propensity for delusions.

Psychotic symptoms as a continuum between normality and pathology

This paper reviews the presence of psychotic features in the nonclinical population. The results of a literature review suggest that delusional and hallucinatory experiences are more common in the general population than we may think, and that there could well be a symptomatic continuum between people who have and people who have not been diagnosed with indisputable psychotic disorders. In the nonclinical population, voices are mainly positive and nonthreatening. Conversely, in the psychiatric population, they tend to be frequent, intrusive, and distressing. We address the question of voices considered as various human experiences and describe the emergence of the nonclinical group of people who hear voices. We also review the pathophysiology of auditory hallucinations as an illustration of a neurophysiological anomaly, which is useful to understand psychosis or schizophrenia. The main obstacle in the category-specific thought is that it remains impossible to unmistakably demarcate the border around schizophrenia. It is evident that the creation of a boundary is always possible by using arbitrary criteria that improve interrater reliability but exclude a considerable number of people who share multiple common features with diagnosed people.

Die Erfassung von Wahn und Halluzinationen in der Normalbevölkerung

Zusammenfassung. Die hohe Prävalenz wahnähnlicher Überzeugungen und halluzinatorischen Erlebens in der Bevölkerung erfordert spezifische Selbstbeurteilungsskalen, die diese subklinischen Phänomene abbilden. In der vorliegenden Untersuchung werden Reliabilität und Validität deutschsprachiger Adaptationen des Peters et al. Delusions Inventory ( Peters, Joseph & Garety, 1999b ) sowie der Launay-Slade Hallucination Scale ( Launay & Slade, 1981 ) an einer in Bezug auf Alter, Geschlecht und Bildungsstand annähernd repräsentativen Stichprobe aus der Normalbevölkerung (n = 359) und einer Stichprobe von Personen mit Schizophrenie (n = 54) untersucht. Beide Skalen weisen eine gute interne Konsistenz sowie hinreichende Kriteriums- und Konstruktvalidität auf. Trotz der Eignung der Skalen zur Differenzierung zwischen Personen mit und Personen ohne Schizophrenie zeigte sich, dass die Items zu wahnähnlichen Überzeugungen und halluzinatorischem Erleben auch in der Bevölkerungsstichprobe in relevanten Ausmaßen bejaht wurden. Weiterhin zeigte sich, dass halluzinatorische Erlebnisse und wahnähnliche Überzeugungen in der Bevölkerung mit erhöhtem psychischen Leidensdruck einhergehen.

Affective traits in schizophrenia and schizotypy

This article reviews empirical studies of affective traits in individuals with schizophrenia spectrum disorders, population-based investigations of vulnerability to psychosis, and genetic and psychometric high-risk samples. The review focuses on studies that use self-report trait questionnaires to assess Negative Affectivity (NA) and Positive Affectivity (PA), which are conceptualized in contemporary models of personality as broad, temperamentally-based dispositions to experience corresponding emotional states. Individuals with schizophrenia report a pattern of stably elevated NA and low PA throughout the illness course. Among affected individuals, these traits are associated with variability in several clinically important features, including functional outcome, quality of life, and stress reactivity. Furthermore, evidence that elevated NA and low PA (particularly the facet of anhedonia) predict the development of psychosis and are detectable in high-risk samples suggests that these traits play a role in vulnerability to schizophrenia, though they are implicated in other forms of psychopathology as well. Results are discussed in terms of their implications for treatment, etiological models, and future research to advance the study of affective traits in schizophrenia and schizotypy.

Finding suitable phenotypes for genetic studies of schizophrenia: heritability and segregation analysis

BACKGROUND

Schizophrenia is a highly heritable and complex disorder. Multiple genes are likely to be involved, complicating genetic research into the etiology of this disorder. Intermediate phenotypes or endophenotypes may facilitate genetic research if they display a simpler mode of transmission than schizophrenia itself, i.e., if they reflect more closely the underlying genetic effects.

METHODS

Twenty-five multigenerational families with multiple members affected with schizophrenia (180 subjects) were administered an extensive neuropsychological, psychophysiological, and personality test battery. Familial correlations were calculated to select heritable traits. Subsequent heritability analysis followed by commingling and segregation analysis were performed to unravel the pattern of transmission and to estimate heritability.

RESULTS

Five traits, including sensorimotor gating, openness, verbal fluency, early visual perception, and spatial working memory, showed moderate familial correlations. Heritability estimates for these traits ranged from 37% to 54%. A major gene model resembling dominant transmission was found for both sensorimotor gating and openness. Verbal fluency, early visual perception, and spatial working memory may be accounted for by polygenic, multifactorial, or environmental effects.

CONCLUSIONS

Only 2 of 13 candidate endophenotypes showed a simple mode of transmission useful for successful application in molecular genetic research: sensorimotor gating and openness. To our knowledge, this is the first study to investigate the pattern of transmission for these traits.

Measuring psychosis proneness in a nonclinical Korean population: is the Peters et al Delusions Inventory useful for assessing high-risk individuals?

OBJECTIVES

We examined the psychometric properties of the Korean version of the Peters et al Delusions Inventory (PDI) 40 and investigated the distribution of delusional ideation in a nonclinical population. We also used the item response theory to evaluate the usefulness of the PDI in measuring the risk for psychosis.

METHODS

A total of 310 nonclinical individuals completed the Korean PDI-40, the Magical Ideation Scale (MIS), and the Schizotypal Personality Scale (STA). In addition, 60 psychotic inpatients with delusions completed the PDI-40. Among 310 individuals, 124 participated in a follow-up study 6 months after completing their original questionnaire.

RESULTS

The PDI-40 revealed a slightly skewed distribution, but the score range was similar to that of the British population. Scores were negatively correlated with age, but no sex differences were found. The Korean PDI-40 exhibited good internal consistency and test-retest reliability. The PDI was significantly correlated with the MIS and the STA. Ten components were extracted through a principal component analysis with varimax rotation. The test results using item response theory revealed 39 items as the items which individuals with very high level of psychosis proneness will answer as "yes." Moreover, all items yielded "above moderate" discrimination in terms of psychosis proneness.

CONCLUSIONS

We confirmed the reliability and validity of the Korean PDI-40. The usefulness of the PDI-40 in a nonclinical population was replicated in the Korean sample. The PDI-40 can be used as an informative device when investigating "psychosis proneness" in a group at high risk for psychosis.

The many faces of psychosis in the elderly

PURPOSE OF REVIEW

As the population ages, the number of older patients with psychosis will greatly rise. This review focuses on the etiology, biologic and clinical findings, and treatments of common causes of psychosis in the elderly.

RECENT FINDINGS

Recent studies on psychosis related to Alzheimer's disease indicate that antipsychotic drugs have equivocal efficacy in improving psychotic symptoms and may have side effects or risks that outweigh their benefits. Behavioral interventions for agitation in dementia are showing some promise. In older adults with schizophrenia, intramuscular ziprasidone was found to be effective, and evidence is emerging for the use of hormone replacement therapy. For depression with psychosis, a recent study found that the combination of an antidepressant with an antipsychotic is no more effective than an antidepressant alone.

SUMMARY

There is support for the use of antipsychotic drugs for all types of psychosis in the elderly. While the atypical antipsychotics have a 'black box warning' on risk of death in elderly patients with dementia, the typical antipsychotics carry an even higher risk of death and adverse effects. Weighing the potential risks and benefits of treatment options is essential. Please refer to your country's regulations regarding the use of antipsychotic drugs.

Mild hearing impairment and psychotic experiences in a normal aging population

BACKGROUND

Hearing impairment (HI) in the elderly may be a risk factor for psychosis, but associations between HI and psychotic disorder or psychotic experiences have been reported more consistently in younger than in older populations. The aims of this study were to replicate the positive association between hearing impairment and psychotic experiences and to clarify any differences between groups of young and old individuals in a non-clinical, normal aging general population sample.

METHODS

HI, assessed at baseline and at 3-year follow-up, and psychotic experiences, assessed at 3-year follow-up, were analysed in a group of 848 individuals aged 33 to 89 years between 1999 and 2004. HI was determined on the basis of both self-report and audiometric examination. The "psychoticism" and "paranoid ideation" subscales from the SCL-90-R were used to assess level of psychotic experiences.

RESULTS

Self-reported hearing problems expressed as conversational HI (beta=0.080, 95% CI: 0.23, 7.90, p=0.038) and subjective HI (beta=0.087, 95%CI: 0.70, 10.30, p=0.025), but not audiometric objective HI, were associated with psychotic experiences. In those with hearing aids, associations with psychotic experiences were only present if accompanied by self-reported hearing problems that persisted in spite of the hearing aid. In addition, HI increased the risk for psychotic experiences specifically in younger rather than older individuals.

CONCLUSIONS

Self-reported hearing problems rather than audiometric or remediated hearing loss may contribute to the development of psychotic experiences in younger rather than in older individuals.