Dimensions of depression, mania and psychosis in the general population

Psychosis superspectrum I: Nosology, etiology, and lifespan development

This review describes the Hierarchical Taxonomy of Psychopathology (HiTOP) model of psychosis-related psychopathology, the psychosis superspectrum. The HiTOP psychosis superspectrum was developed to address shortcomings of traditional diagnoses for psychotic disorders and related conditions including low reliability, arbitrary boundaries between psychopathology and normality, high symptom co-occurrence, and heterogeneity within diagnostic categories. The psychosis superspectrum is a transdiagnostic dimensional model comprising two spectra-psychoticism and detachment-which are in turn broken down into fourteen narrow components, and two auxiliary domains-cognition and functional impairment. The structure of the spectra and their components are shown to parallel the genetic structure of psychosis and related traits. Psychoticism and detachment have distinct patterns of association with urbanicity, migrant and ethnic minority status, childhood adversity, and cannabis use. The superspectrum also provides a useful model for describing the emergence and course of psychosis, as components of the superspectrum are relatively stable over time. Changes in psychoticism predict the onset of psychosis-related psychopathology, whereas changes in detachment and cognition define later course. Implications of the superspectrum for genetic, socio-environmental, and longitudinal research are discussed. A companion review focuses on neurobiology, treatment response, and clinical utility of the superspectrum, and future research directions.

Longitudinal symptomatic interactions in long-standing schizophrenia: a novel five-point analysis based on directed acyclic graphs

BACKGROUND

Recent network models propose that mutual interaction between symptoms has an important bearing on the onset of schizophrenic disorder. In particular, cross-sectional studies suggest that affective symptoms may influence the emergence of psychotic symptoms. However, longitudinal analysis offers a more compelling test for causation: the European Schizophrenia Cohort (EuroSC) provides data suitable for this purpose. We predicted that the persistence of psychotic symptoms would be driven by the continuing presence of affective disturbance.

METHODS

EuroSC included 1208 patients randomly sampled from outpatient services in France, Germany and the UK. Initial measures of psychotic and affective symptoms were repeated four times at 6-month intervals, thereby furnishing five time-points. To examine interactions between symptoms both within and between time-slices, we adopted a novel technique for modelling longitudinal data in psychiatry. This was a form of Bayesian network analysis that involved learning dynamic directed acyclic graphs (DAGs).

RESULTS

Our DAG analysis suggests that the main drivers of symptoms in this long-term sample were delusions and paranoid thinking. These led to affective disturbance, not vice versa as we initially predicted. The enduring relationship between symptoms was unaffected by whether patients were receiving first- or second-generation antipsychotic medication.

CONCLUSIONS

In this cohort of people with chronic schizophrenia treated with medication, symptoms were essentially stable over long periods. However, affective symptoms appeared driven by the persistence of delusions and persecutory thinking, a finding not previously reported. Although our findings as ever remain hostage to unmeasured confounders, these enduring psychotic symptoms might nevertheless be appropriate candidates for directly targeted psychological interventions.

Heart rate variability is associated with disease severity in psychosis spectrum disorders

While a growing literature links cardiac autonomic dysregulation to a variety of psychiatric disorders, the relationship between cardiac autonomic functioning and specific symptoms in schizophrenia (SZ) and bipolar disorder (BD) remains elusive. Thus, we investigated heart rate variability (HRV), a proxy for vagal activity, as a biological marker for symptom severity in patients with SZ and BD. HRV was calculated in 35 patients with SZ and 52 patients with BD, as well as in 149 healthy controls. In the patient groups, symptom severity and function were measured by the Positive and Negative Syndrome Scale (PANSS) and the Global Assessment of Functioning (GAF) scale. Results showed that HRV was significantly lower in both clinical groups compared to the healthy controls, with no significant HRV differences between patient groups. PANSS general psychopathology scores, GAF symptom scores, and GAF function scores showed statistically significant associations with HRV across groups. These results suggest that disease severity is associated with autonomic dysfunction and that HRV may provide a potential biomarker of disease severity in SZ and BD.

Experiential avoidance mediates the association between paranoid ideation and depressive symptoms in a sample from the general population

Psychotic experiences are prevalent in the general population and are associated with negative outcomes, including depressive symptoms. The mechanisms underlying this relationship remain unclear, but new insights could be obtained by exploring the role of transdiagnostic processes such as experiential avoidance, defined as a person's attempts or desires to suppress unwanted internal experiences like thoughts, emotions, memories, or bodily sensations. Studies analyzing the link between negative emotional states and psychotic experiences are scant. We explored the association between a specific kind of psychotic experience (paranoid ideation), experiential avoidance, and depressive, anxiety, and stress symptoms in a sample from the general population. We found that experiential avoidance partially mediates the associations between paranoid ideation and stress and anxiety symptoms and that it fully mediates the association between paranoid ideation and depressive symptoms. Our results suggest that the presence of paranoid ideation and the usage of experiential avoidance to cope with it are vulnerability factors associated with psychological distress.

Reviewing the diagnostic validity and utility of mixed depression (depressive mixed states)

Objective

To review the diagnostic validity and utility of mixed depression, i.e. co-occurrence of depression and manic/hypomanic symptoms.

Methods

PubMed search of all English-language papers published between January 1966 and December 2006 using and cross-listing key words: bipolar disorder, mixed states, criteria, utility, validation, gender, temperament, depression-mixed states, mixed depression, depressive mixed state/s, dysphoric hypomania, mixed hypomania, mixed/dysphoric mania, agitated depression, anxiety disorders, neuroimaging, pathophysiology, and genetics. A manual review of paper reference lists was also conducted.

Results

By classic diagnostic validators, the diagnostic validity of categorically-defined mixed depression (i.e. at least 2–3 manic/hypomanic symptoms) is mainly supported by family history (the current strongest diagnostic validator). Its diagnostic utility is supported by treatment response (negative effects of antidepressants). A dimensionally-defined mixed depression is instead supported by a non-bi-modal distribution of its intradepression manic/hypomanic symptoms.

Discussion

Categorically-defined mixed depression may have some diagnostic validity (family history is the current strongest validator). Its diagnostic utility seems supported by treatment response.

Dimensional and discrete variations on the psychosis continuum in a Dutch crowd-sourcing population sample

Background

Mild psychotic experiences are common in the general population. Although transient and benign in most cases, these experiences are predictive of later mental health problems for a significant minority. The goal of the present study was to perform examinations of the dimensional and discrete variations in individuals’ reporting of subclinical positive and negative psychotic experiences in a unique Dutch internet-based sample from the general population.

Methods

Positive and negative subclinical psychotic experiences were measured with the Community Assessment of Psychic Experiences in 2870 individuals. First, the prevalence of these experiences and their associations with demographics, affect, psychopathology and quality of life were investigated. Next, latent class analysis was used to identify data-driven subgroups with different symptom patterns, which were subsequently compared on aforementioned variables.

Results

Subclinical psychotic experiences were commonly reported. Both positive and negative psychotic experiences were associated with younger age, more negative affect, anxiety and depression as well as less positive affect and poorer quality of life. Seven latent classes (‘Low psychotic experiences’, ‘Lethargic’, ‘Blunted’, ‘Distressed’, ‘Paranormal’, ‘Distressed_grandiose’ and ‘Distressed/positive psychotic experiences’) were identified that demonstrated both dimensional differences in the number/severity of psychotic experiences and discrete differences in the patterns of reported experiences.

Conclusion

Subclinical psychotic experiences show both dimensional severity variations and discrete symptom-pattern variations across individuals. To understand and capture all interindividual variations in subclinical psychotic experiences, their number, nature and context (co-occurrence patterns) should be considered at the same time. Only some psychotic experiences may lay on a true psychopathological psychosis continuum.

Links between psychotic and neurotic symptoms in the general population: an analysis of longitudinal British National Survey data using Directed Acyclic Graphs

BACKGROUND

Non-psychotic affective symptoms are important components of psychotic syndromes. They are frequent and are now thought to influence the emergence of paranoia and hallucinations. Evidence supporting this model of psychosis comes from recent cross-fertilising epidemiological and intervention studies. Epidemiological studies identify plausible targets for intervention but must be interpreted cautiously. Nevertheless, causal inference can be strengthened substantially using modern statistical methods.

METHODS

Directed Acyclic Graphs were used in a dynamic Bayesian network approach to learn the overall dependence structure of chosen variables. DAG-based inference identifies the most likely directional links between multiple variables, thereby locating them in a putative causal cascade. We used initial and 18-month follow-up data from the 2000 British National Psychiatric Morbidity survey (N = 8580 and N = 2406).

RESULTS

We analysed persecutory ideation, hallucinations, a range of affective symptoms and the effects of cannabis and problematic alcohol use. Worry was central to the links between symptoms, with plausible direct effects on insomnia, depressed mood and generalised anxiety, and recent cannabis use. Worry linked the other affective phenomena with paranoia. Hallucinations were connected only to worry and persecutory ideation. General anxiety, worry, sleep problems, and persecutory ideation were strongly self-predicting. Worry and persecutory ideation were connected over the 18-month interval in an apparent feedback loop.

CONCLUSIONS

These results have implications for understanding dynamic processes in psychosis and for targeting psychological interventions. The reciprocal influence of worry and paranoia implies that treating either symptom is likely to ameliorate the other.

Why are psychotic experiences associated with self-injurious thoughts and behaviours? A systematic review and critical appraisal of potential confounding and mediating factors

Psychotic experiences (PEs), including hallucination- and delusion-like experiences, are robustly associated with self-injurious thoughts and behaviours (SITB) in the general population. However, it remains unclear as to why there is an association. The purpose of this systematic review was to elucidate the role of other factors that influence the association between PEs and SITB and, in doing so, highlight potential mechanisms underlying the relationship. A search of electronic international databases was undertaken, including PubMed, PsycINFO and EMBASE, and eligible studies were grouped according to seven confounder categories: sociodemographics, mental disorders, alcohol and substance use, environmental, psychological, intervention and family history/genetic factors. The systematic search strategy identified 41 publications reporting on 1 39 427 participants from 16 different countries. In the majority of studies, where adjustment for other variables occurred, the association between PEs and SITB persisted, suggesting PEs have an independent role. Common mental disorders, psychological distress and negative environmental exposures explained a substantial amount of the variance and therefore need to be considered as potential underlying mechanisms. There was high variability in the variables adjusted for in these studies, and so the question still remains as to whether the association between PEs and self-harm/suicidality can be attributed (fully or in part) to confounding and mediating factors or directly causal mechanisms. Regardless of causality, the now extensive literature reporting an association between these two clinical phenomena supports the broad usefulness of PEs as an indicator of risk for SITB.

The slow death of the concept of schizophrenia and the painful birth of the psychosis spectrum

The concept of schizophrenia only covers the 30% poor outcome fraction of a much broader multidimensional psychotic syndrome, yet paradoxically has become the dominant prism through which everything 'psychotic' is observed, even affective states with mild psychosis labelled 'ultra-high risk' (for schizophrenia). The inability of psychiatry to frame psychosis as multidimensional syndromal variation of largely unpredictable course and outcome - within and between individuals - hampers research and recovery-oriented practice. 'Psychosis' remains firmly associated with 'schizophrenia', as evidenced by a vigorous stream of high-impact but non-replicable attempts to 'reverse-engineer' the hypothesized biological disease entity, using case-control paradigms that cannot distinguish between risk for illness onset and risk for poor outcome. In this paper, the main issues surrounding the concept of schizophrenia are described. We tentatively conclude that with the advent of broad spectrum phenotypes covering autism and addiction in DSM5, the prospect for introducing a psychosis spectrum disorder - and modernizing psychiatry - appears to be within reach.

The longitudinal association between external locus of control, social cognition and adolescent psychopathology

PURPOSE

To investigate the longitudinal associations between social cognitive ability an external locus of control (externality) and adolescent psychopathology.

METHODS

7058 participants from a prospective population-based cohort provided data on externality, social communication, and emotion perception between 7 and 16 years and psychotic experiences and depressive symptoms at 12 and 18 years. Bivariate probit modelling was used to investigate associations between these risk factors and psychopathological outcomes.

RESULTS

Externality was associated with psychopathology at 12 (psychotic experiences OR 1.23 95% CI 1.14, 1.33; depression OR 1.12 95% CI 1.02, 1.22) and 18 years (psychotic experiences OR 1.38 95% CI 1.23, 1.55; depression OR 1.40 95% CI 1.28, 1.52). Poor social communication was associated with depression at both ages (12 years OR 1.22 95% CI 1.11, 1.34; 18 years OR 1.21 95% CI 1.10, 1.33) and marginally associated with psychotic experiences. There was marginal evidence of a larger association between externality and psychotic experiences at 12 years (p = 0.06) and between social communication and depression at 12 years (p = 0.03).

CONCLUSIONS

Externality was more strongly associated with psychotic experiences. At 18 years change in externality, between 8 and 16 years were associated with a larger increase in the risk of depression. Poor social communication was more strongly associated with depression.

Cingulo-opercular network efficiency mediates the association between psychotic-like experiences and cognitive ability in the general population

BACKGROUND

Psychosis is hypothesized to occur on a spectrum between psychotic disorders and healthy individuals. In the middle of the spectrum are individuals who endorse psychotic-like experiences (PLEs) that may not impact daily functioning or cause distress. Individuals with PLEs show alterations in both cognitive ability and functional connectivity of several brain networks, but the relationship between PLEs, cognition, and functional networks remains poorly understood.

METHODS

We analyzed resting-state fMRI data, a range of neuropsychological tasks, and questions from the Achenbach Adult Self Report (ASR) in 468 individuals from the Human Connectome Project. We aimed to determine whether global efficiency of specific functional brain networks supporting higher-order cognition (the fronto-parietal network (FPN), cingulo-opercular network (CON), and default mode network (DMN)) was associated with PLEs and cognitive ability in a non-psychiatric sample.

RESULTS

21.6% of individuals in our sample endorsed at least one PLE. PLEs were significantly negatively associated with higher-order cognitive ability, CON global efficiency, and DMN global efficiency, but not crystallized knowledge. Higher-order cognition was significantly positively associated with CON and DMN global efficiency. Interestingly, the association between PLEs and cognitive ability was partially mediated by CON global efficiency and, in a subset of individuals who tested negative for drugs (N=405), the participation coefficient of the right anterior insula (a hub within the CON).

CONCLUSIONS

These findings suggest that CON integrity may represent a shared mechanism that confers risk for psychotic experiences and the cognitive deficits observed across the psychosis spectrum.

Clinical, socio-demographic and psychological characteristics in individuals with persistent psychotic experiences with and without a "need for care"

Individuals reporting persistent psychotic experiences (PEs) in the general population, but without a "need for care", are a unique group of particular importance in identifying risk and protective factors for psychosis. We compared people with persistent PEs and no "need for care" (non-clinical, N=92) with patients diagnosed with a psychotic disorder (clinical, N=84) and controls without PEs (N=83), in terms of their phenomenological, socio-demographic and psychological features. The 259 participants were recruited from one urban and one rural area in the UK, as part of the UNIQUE (Unusual Experiences Enquiry) study. Results showed that the non-clinical group experienced hallucinations in all modalities as well as first-rank symptoms, with an earlier age of onset than in the clinical group. Somatic/tactile hallucinations were more frequent than in the clinical group, while commenting and conversing voices were rare. Participants in the non-clinical group were differentiated from their clinical counterparts by being less paranoid and deluded, apart from ideas of reference, and having fewer cognitive difficulties and negative symptoms. Unlike the clinical group, they were characterized neither by low psychosocial functioning nor by social adversity. However, childhood trauma featured in both groups. They were similar to the controls in psychological characteristics: they did not report current emotional problems, had intact self-esteem, displayed healthy schemas about the self and others, showed high life satisfaction and well-being, and high mindfulness. These findings support biopsychosocial models postulating that environmental and psychological factors interact with biological processes in the aetiology of psychosis. While some PEs may be more malign than others, lower levels of social and environmental adversity, combined with protective factors such as intact IQ, spirituality, and psychological and emotional well-being, may reduce the likelihood of persistent PEs leading to pathological outcomes. Future research should focus on protective factors and determinants of well-being in the context of PEs, rather than exclusively on risk factors and biomarkers of disease states.

[Relationship between subclinical psychotic symptoms and cognitive performance in the general population]

INTRODUCTION

Subclinical psychotic symptoms are associated to negative life outcomes in the general population, but their relationship with cognitive performance is still not well understood. Assessing the relationship between performance in cognitive domains and subclinical psychotic symptoms in the general population may also help understand the handicap attributed to clinical psychosis, in which these alterations are present.

METHODS

Subclinical and cognitive assessments were obtained in 203 participants from the general population by means of the Community Assessment of Psychic Experiences, the Brief Assessment of Cognition in Schizophrenia, the Wechsler Adults Intelligence Scale and the Wisconsin Card Sorting Test. The positive and negative subclinical symptoms and their relationship with age and cognition were examined, followed by assessing the influence of subclinical depression scores on the possible relationships between those subclinical psychotic symptoms and cognitive deficits.

RESULTS

Inverse relationships were found between frequency in the Community Assessment of Psychic Experiences positive dimension and motor speed, and frequency and distress in the Community Assessment of Psychic Experiences negative dimension and motor speed. A direct relationship was also found between distress scores of the positive dimension and executive functions. Both positive and negative subclinical symptoms were related to depression scores.

CONCLUSIONS

Psychotic symptoms, similar to those in the clinical population, may be associated with cognitive deficits in the general population.

Examining the Psychosis Continuum

The notion that psychosis may exist on a continuum with normal experience has been proposed in multiple forms throughout the history of psychiatry. However, in recent years there has been an exponential increase in efforts aimed at elucidating what has been termed the 'psychosis continuum'. The present review seeks to summarize some of the more basic characteristics of this continuum and to present some of the recent findings that provide support for its validity. While there is still considerable work to be done, the emerging data holds considerable promise for advancing our understanding of both risk and resilience to psychiatric disorders characterized by psychosis.

Cannabis use and mania symptoms: a systematic review and meta-analysis

BACKGROUND

Whilst cannabis use appears to be a causal risk factor for the development of schizophrenia-related psychosis, associations with mania remain relatively unknown. This review aimed to examine the impact of cannabis use on the incidence of manic symptoms and on their occurrence in those with pre-existing bipolar disorder.

METHODS

A systematic review of the scientific literature using the PRISMA guidelines. PsychINFO, Cochrane, Scopus, Embase and MEDLINE databases were searched for prospective studies.

RESULTS

Six articles met inclusion criteria. These sampled 2391 individuals who had experienced mania symptoms. The mean length of follow up was 3.9 years. Studies support an association between cannabis use and the exacerbation of manic symptoms in those with previously diagnosed bipolar disorder. Furthermore, a meta-analysis of two studies suggests that cannabis use is associated with an approximately 3-fold (Odds Ratio: 2.97; 95% CI: 1.80-4.90) increased risk for the new onset of manic symptoms.

LIMITATIONS

We were only able to identify a small number of studies of variable quality, thus our conclusions remain preliminary.

CONCLUSIONS

Our findings whilst tentative, suggest that cannabis use may worsen the occurrence of manic symptoms in those diagnosed with bipolar disorder, and may also act as a causal risk factor in the incidence of manic symptoms. This underscores the importance of discouraging cannabis use among youth and those with bipolar disorder to help prevent chronic psychiatric morbidity. More high quality prospective studies are required to fully elucidate how cannabis use may contribute to the development of mania over time.

Reduced brain reward response during cooperation in first-degree relatives of patients with psychosis: an fMRI study

BACKGROUND

Psychosis is characterized by a profound lack of trust and disturbed social interactions. Investigating the neural basis of these deficits is difficult because of medication effects but first-degree relatives show qualitatively similar abnormalities to patients with psychosis on various tasks. This study aimed to investigate neural activation in siblings of patients in response to an interactive task. We hypothesized that, compared to controls, siblings would show (i) less basic trust at the beginning of the task and (ii) reduced activation of the brain reward and mentalizing systems.

METHOD

Functional magnetic resonance imaging (fMRI) data were acquired on 50 healthy siblings of patients with psychosis and 33 healthy controls during a multi-round trust game with a cooperative counterpart. An a priori region-of-interest (ROI) analysis of the caudate, temporoparietal junction (TPJ), superior temporal sulcus (STS), insula and medial prefrontal cortex (mPFC) was performed focusing on the investment and repayment phases. An exploratory whole-brain analysis was run to test for group-wise differences outside these ROIs.

RESULTS

The siblings' behaviour during the trust game did not differ significantly from that of the controls. At the neural level, siblings showed reduced activation of the right caudate during investments, and the left insula during repayments. In addition, the whole-brain analysis revealed reduced putamen activation in siblings during investments.

CONCLUSIONS

The findings suggest that siblings show aberrant functioning of regions traditionally involved in reward processing in response to cooperation, which may be associated with the social reward deficits observed in psychosis.

Common versus psychopathology-specific risk factors for psychotic experiences and depression during adolescence

BACKGROUND

An argument often used to support the view that psychotic experiences (PEs) in general population samples are a valid phenotype for studying the aetiology of schizophrenia is that risk factors for schizophrenia show similar patterns of association with PEs. However, PEs often co-occur with depression, and no study has explicitly tested whether risk factors for schizophrenia are shared between PEs and depression, or are psychopathology specific, while jointly modelling both outcomes.

METHOD

We used data from 7030 subjects from a birth cohort study. Depression and PEs at age 18 years were assessed using self-report questionnaires and semi-structured interviews. We compared the extent to which risk factors for schizophrenia across sociodemographic, familial, neurodevelopmental, stress-adversity, emotional-behavioural and substance use domains showed different associations with PEs and depression within bivariate models that allowed for their correlation.

RESULTS

Most of the exposures examined were associated, to a similar degree, with an increased risk of both outcomes. However, whereas female sex and family history of depression showed some discrimination as potential risk factors for depression and PEs, with stronger associations in the former, markers of abnormal neurodevelopment showed stronger associations with PEs.

CONCLUSIONS

The argument that PEs are valid markers for studying the aetiology of schizophrenia, made simply on the basis that they share risk factors in common, is not well supported. PEs seem to be a weak index of genetic and environmental risk for schizophrenia; however, studies disentangling aetiological pathways to PEs from those impacting upon co-morbid psychopathology might provide important insights into the aetiology of psychotic disorders.

Psychopathological mechanisms linking childhood traumatic experiences to risk of psychotic symptoms: analysis of a large, representative population-based sample

BACKGROUND

Different psychological models of trauma-induced psychosis have been postulated, often based on the observation of "specific" associations between particular types of childhood trauma (CT) and particular psychotic symptoms or the co-occurrence of delusions and hallucinations. However, the actual specificity of these associations remains to be tested.

METHODS

In 2 population-based studies with comparable methodology (Netherlands Mental Health Survey and Incidence Study-1 [NEMESIS-1] and NEMESIS-2, N = 13 722), trained interviewers assessed CT, psychotic symptoms, and other psychopathology. Specificity of associations was assessed with mixed-effects regression models with multiple outcomes, a statistical method suitable to examine specificity of associations in case of multiple correlated outcomes.

RESULTS

Associations with CT were strong and significant across the entire range of psychotic symptoms, without evidence for specificity in the relationship between particular trauma variables and particular psychotic experiences (PEs). Abuse and neglect were both associated with PEs (OR abuse: 2.12, P < .001; OR neglect: 1.96, P < .001), with no large or significant difference in effect size. Intention-to-harm experiences showed stronger associations with psychosis than CT without intent (χ(2) = 58.62, P < .001). Most trauma variables increased the likelihood of co-occurrence of delusions and hallucinations rather than either symptom in isolation.

DISCUSSION

Intention to harm is the key component linking childhood traumatic experiences to psychosis, most likely characterized by co-occurrence of hallucinations and delusions, indicating buildup of psychotic intensification, rather than specific psychotic symptoms in isolation. No evidence was found to support psychological theories regarding specific associations between particular types of CT and particular psychotic symptoms.

Depressive symptoms are associated with (sub)clinical psychotic symptoms in patients with non-affective psychotic disorder, siblings and healthy controls

BACKGROUND

Depression is a clinically relevant dimension, associated with both positive and negative symptoms, in patients with schizophrenia. However, in siblings it is unknown whether depression is associated with subclinical positive and negative symptoms. Method Depressive symptoms and their association with positive and negative symptoms were examined in 813 healthy siblings of patients with a non-affective psychotic disorder, 822 patients and 527 healthy controls. Depressive episodes meeting DSM-IV-TR criteria (lifetime) and depressed mood (lifetime) were assessed with the Comprehensive Assessment of Symptoms and History (CASH) in all three groups. In the patient group, the severity of positive and negative psychosis symptoms was assessed with the CASH. In the siblings and healthy controls, the severity of subclinical psychosis symptoms was assessed with the Community Assessment of Psychic Experiences (CAPE).

RESULTS

Patients reported more lifetime depressed mood and more depressive episodes than both siblings and controls. Siblings had a higher chance of meeting lifetime depressive episodes than the controls; no significant differences in depressed mood were found between siblings and controls. In all three groups the number and duration of depressive symptoms were associated with (sub)clinical negative symptoms. In the patients and siblings the number of depressive symptoms was furthermore associated with (sub)clinical positive symptoms. Finally, lifetime depressed mood showed familial clustering but this clustering was absent for lifetime depressive episodes.

CONCLUSIONS

These findings suggest that a co-occurring genetic vulnerability for both depressive and psychotic symptomatology exists on a clinical and a subclinical level.

Self-perception but not peer reputation of bullying victimization is associated with non-clinical psychotic experiences in adolescents

BACKGROUND

Bullying victimization may be linked to psychosis but only self-report measures of victimization have been used so far. This study aimed (a) to investigate the differential associations of peer-nominated versus self-reported victim status with non-clinical psychotic experiences in a sample of young adolescents, and (b) to examine whether different types of self-reported victimization predict non-clinical psychotic experiences in these adolescents. Method A combination of standard self-report and peer nomination procedures was used to assess victimization. The sample (n = 724) was divided into four groups (exclusively self-reported victims, self- and peer-reported victims, exclusively peer-reported victims, and non-victims) to test for a group effect on non-clinical psychotic experiences. The relationship between types of victimization and non-clinical psychotic experiences was examined by a regression analysis.

RESULTS

Self-reported victims, along with self- and peer-reported victims, scored higher than peer-reported victims and non-victims on non-clinical psychotic experiences. Self-reports of direct relational, indirect relational and physical victimization significantly improved the prediction of non-clinical psychotic experiences whereas verbal and possession-directed victimization had no significant predictive value.

CONCLUSIONS

The relationship between victimization and non-clinical psychotic experiences is only present for self-reported victimization, possibly indicative of an interpretation bias. The observed discrepancy between self-report and peer-report highlights the importance of implementing a combination of both measures for future research.

The heritability of delusional-like experiences

OBJECTIVE

Delusional-like experiences (DLE) are common in the general community and are associated with a family history of mental illness. The aim of this study was to estimate the heritability of DLE.

METHOD

The Peter's Delusional Inventory (PDI) was administered to a population-based cohort of mothers (n = 2861, aged 35-67 years) and their adult offspring (n = 3079, aged 18-23 years). Heritability of DLE was estimated from the sum scores of the 21 item PDI under the assumption that the covariance between mother-offspring scores is attributable to shared additive genetic factors.

RESULTS

The means (medians and standard deviations) for the total PDI scores for the mothers and their offspring were 3.6 (3.0, 3.0) and 5.0 (4.0, 3.5), respectively. The Pearson correlation coefficient between mother and offspring PDI scores was 0.17 (P < 0.001). The heritability was estimated to be 0.35 (standard error 0.04).

CONCLUSION

Heritable factors contribute to over a third of the variance of PDI scores in this population. In light of the association between a family history of a wide range of mental disorders and DLE, these experiences may represent a useful quantitative endophenotype for genetic studies of common mental disorders in population settings.

Categorical vs dimensional classifications of psychotic disorders

OBJECTIVE

Both categorical and dimensional methods appear relevant to classifying psychotic disorders; however, there is no clear consensus on the most appropriate categories and dimensions or on the best approach for constructing nosologic criteria that integrate these 2 methods. This review examines the evidence on specific dimensions and categories that would best characterize psychoses.

METHOD

Entries in the MEDLINE database between 1980 and 2011 were searched for studies of the dimensional and/or categorical structure of psychosis. Studies were included if samples represented a spectrum of psychotic disorders and dimensions/categories were empirically derived using principal components analysis, factor analysis, or latent class analysis.

RESULTS

Most dimensional studies observed 4 or 5 dimensions within psychosis, with positive, negative, disorganization, and affective symptom domains most frequently reported. Substance abuse, anxiety, early onset/developmental, insight, cognition, hostility, and behavioral/social disturbance dimensions appeared in some studies. Categorical studies suggested 3 to 7 major classes within psychosis, including a class similar to Kraepelin's dementia praecox and one or more classes with significant mood components. Only 2 studies compared the relative fit of empirically derived dimensions and categories within the same data set, and each had significant limitations.

CONCLUSION

There is relatively consistent evidence on appropriate categories and dimensions for characterizing psychoses. However, the lack of studies directly comparing or combining these approaches provides insufficient evidence for definitive conclusions about their relative merits and integration. The authors provide specific recommendations for designing future studies to identify valid dimensions and/or categories of the psychoses and investigate hybrid approaches to model the structure of the underlying illnesses.

Testing the psychosis continuum: differential impact of genetic and nongenetic risk factors and comorbid psychopathology across the entire spectrum of psychosis

A growing number of studies demonstrate high rates of subthreshold psychotic experiences, but there is considerable heterogeneity in rates due to study cohort and design factors, obscuring how prevalent psychotic experiences may or may not relate to rare psychotic disorders. In a representative general population sample (n = 4011) in Izmir, Turkey, the full spectrum of expression of psychosis was categorized across 5 groups representing (1) absence of psychosis, (2) subclinical psychotic experiences, (3) low-impact psychotic symptoms, (4) high-impact psychotic symptoms, and (5) full-blown clinical psychotic disorder and analyzed for continuity and discontinuity in relation to (1) other symptom dimensions associated with psychotic disorder and (2) proxies of genetic and nongenetic etiology. Results were tested for linear and extralinear contrasts between clinical and nonclinical and between disorder and nondisorder expression of psychosis. Demographic variables, indexing premorbid social adjustment and socioeconomic status, impacted mostly linearly; proxy variables of genetic loading (more or more severely affected relatives) impacted in a positive extralinear fashion; environmental risk factors sometimes impacted linearly (urbanicity and childhood adversity) and sometimes extralinearly (cannabis), occasioning a disproportional shift in risk at the clinical disorder end of the spectrum. Affective symptoms were associated with a disproportionally higher risk below the disorder threshold, whereas a disproportionally higher risk above the threshold was associated with psychotic symptom load, negative symptoms, disorganization, and visible signs of mental illness. Liability associated with respectively affective and nonaffective symptom domains, in interaction with environmental risks, may operate by impacting differentially over a quasi-continuous extended psychosis phenotype in the population.

Predictive factors for time to remission and recurrence in patients treated for acute mania: health outcomes of manic episodes (HOME) study

OBJECTIVE

To determine the time to remission and recurrence in patients treated for acute mania and the predictive factors associated with these outcomes.

METHOD

This observational study, conducted in Turkey from April 2003 to January 2005, included patients with a DSM-IV diagnosis of bipolar I disorder, acute manic or mixed episode who were eligible to have an oral medication initiated or changed for the treatment of the episode. The patients were followed-up for 12 months.

RESULTS

A total of 584 patients (mean ± SD age = 33.9 ± 11.2, 55.2% outpatients) were enrolled in 53 centers. Eighty-five percent of patients had a manic episode at baseline, with a mean ± SD duration of 21.6 ± 24.4 days. The baseline mean ± SD Clinical Global Impressions scale for use in bipolar disorder and Young Mania Rating Scale (YMRS) scores were 4.9 ± 0.9 (median = 5.0) and 33.2 ± 9.3 (median = 33), respectively. 539 patients achieved remission and, of those, 141 patients had recurrence. One-year remission and recurrence rates were 99.0% and 35.7%, respectively. Mean ± SD times to remission and recurrence in descriptive statistics were 80.9 ± 73.8 (median = 50) and 159.0 ± 95.5 (median = 156) days, respectively. In Cox regression analysis, psychiatric comorbidities (p = .048), a higher YMRS score (p < .001), and a higher number of previous depressive episodes (p = .009) were statistically significant predictors of a longer time to reach remission. Index episodes of longer duration (p = .033) and mixed type (p = 0.49) were significant predictors of a shorter time to recurrence. Confounding factors like concomitant treatment, comorbidities, and lack of blinding and randomization were other limitations.

CONCLUSION

Predictors for a longer time to remission were psychiatric comorbidities, a higher YMRS score, and a higher number of previous depressive episodes. Predictors for a shorter time to recurrence were episodes of longer duration and mixed type.

Psychotic-like experiences in a community sample of 8000 children aged 9 to 11 years: an item response theory analysis

BACKGROUND

Psychotic-like experiences (PLEs) in the general population are common, particularly in childhood, and may constitute part of a spectrum of normative development. Nevertheless, these experiences confer increased risk for later psychotic disorder, and are associated with poorer health and quality of life.

METHOD

This study used factor analytic methods to determine the latent structure underlying PLEs, problem behaviours and personal competencies in the general child population, and used item response theory (IRT) to assess the psychometric properties of nine PLE items to determine which items best represented a latent psychotic-like construct (PSY). A total of 7966 children aged 9-11 years, constituting 95% of eligible children, completed self-report questionnaires.

RESULTS

Almost two-thirds of the children endorsed at least one PLE item. Structural analyses identified a unidimensional construct representing psychotic-like severity in the population, the full range of which was well sampled by the nine items. This construct was discriminable from (though correlated with) latent dimensions representing internalizing and externalizing problems. Items assessing visual and auditory hallucination-like experiences provided the most information about PSY; delusion-like experiences identified children at more severe levels of the construct.

CONCLUSIONS

Assessing PLEs during middle childhood is feasible and supplements information concerning internalizing and externalizing problems presented by children. The hallucination-like experiences constitute appropriate items to screen the population to identify children who may require further clinical assessment or monitoring. Longitudinal follow-up of the children is required to determine sensitivity and specificity of the PLE items for later psychotic illness.

Phenotypically continuous with clinical psychosis, discontinuous in need for care: evidence for an extended psychosis phenotype

BACKGROUND

Rates of self-reported psychotic experiences (SRPEs) in general population samples are high; however the reliability against interview-based assessments and the clinical significance of false-positive (FP) ratings remain unclear.

DESIGN

The second Netherlands Mental Health Survey and Incidence Study-2, a general population study.

METHODS

Trained lay interviewers administered a structured interview assessing psychopathology and psychosocial characteristics in 6646 participants. Participants with at least one SRPE (N = 1084) were reassessed by clinical telephone interview.

RESULTS

Thirty-six percent of participants with SRPEs were confirmed by clinical interview as true positive (TP). SPREs not confirmed by clinical interview (FP group) generated less help-seeking behavior and occurred less frequently compared with TP experiences (TP group). However, compared with controls without psychotic experiences, the FP group more often displayed mood disorder (relative risk [RR] 1.7, 1.4-2.2), substance use disorder (RR 2.0, 1.6-2.6), cannabis use (RR 1.5, 1.2-1.9), higher levels of neuroticism (RR 1.8, 1.5-2.2), affective dysregulation, and social dysfunction. The FP group also experienced more sexual (RR 2.0, 1.5-2.8) and psychological childhood trauma (RR 2.1, 1.7-2.6) as well as peer victimization (RR 1.5, 1.2-2.0) and recent life events (RR 2.0, 1.6-2.4) than controls without psychotic experiences. Differences between the FP group and the TP group across these domains were much smaller and less conclusive.

DISCUSSION

SRPEs not confirmed by clinical interview may represent the softest expression of an extended psychosis phenotype that is phenotypically continuous with clinical psychosis but discontinuous in need for care.

Evidence that psychotic symptoms are prevalent in disorders of anxiety and depression, impacting on illness onset, risk, and severity--implications for diagnosis and ultra-high risk research

BACKGROUND

It is commonly assumed that there are clear lines of demarcation between anxiety and depressive disorders on the one hand and psychosis on the other. Recent evidence, however, suggests that this principle may be in need of updating.

METHODS

Depressive and/or anxiety disorders, with no previous history of psychotic disorder, were examined for the presence of psychotic symptoms in a representative community sample of adolescents and young adults (Early Developmental Stages of Psychopathology study; n = 3021). Associations and consequences of psychotic symptomatology in the course of these disorders were examined in terms of demographic distribution, illness severity, onset of service use, and risk factors.

RESULTS

Around 27% of those with disorders of anxiety and depression displayed one or more psychotic symptoms, vs 14% in those without these disorders (OR 2.23, 95% CI 1.89-2.66, P < .001). Presence as compared with nonpresence of psychotic symptomatology was associated with younger age (P < .0001), male sex (P < .0058), and poorer illness course (P < .0002). In addition, there was greater persistence of schizotypal (P < .0001) and negative symptoms (P < .0170), more observable illness behavior (P < .0001), greater likelihood of service use (P < .0069), as well as more evidence of familial liability for mental illness (P < .0100), exposure to trauma (P < .0150), recent and more distant life events (P < .0006-.0244), cannabis use (P < .0009), and any drug use (P < .0008).

CONCLUSION

Copresence of psychotic symptomatology in disorders of anxiety and depression is common and a functionally and etiologically highly relevant feature, reinforcing the view that psychopathology is represented by a network or overlapping and reciprocally impacting dimensional liabilities.

Evidence that genes for depression impact on the pathway from trauma to psychotic-like symptoms by occasioning emotional dysregulation

BACKGROUND

Genes for depression may act by making individuals more sensitive to childhood trauma. Given that childhood adversity is a risk factor for adult psychosis and symptoms of depression and psychosis tend to cluster within individuals and families, the aim was to examine whether the association between childhood adversity and psychotic-like symptoms is moderated by genetic liability for depression. A secondary aim was to determine to what degree a depression-related increase in stress sensitivity or depressive symptoms themselves occasioned the moderating effect.

METHOD

Female twins (n=508) completed both prospective and retrospective questionnaires regarding childhood adversity [the Symptom Checklist-90 - Revised (SCL-90-R) and SCID-I (psychotic symptoms)] and psychotic trait liability [the Community Assessment of Psychic Experiences (CAPE)]. Stress sensitivity was indexed by appraisals of event-related stress and negative affect (NA) in the flow of daily life, assessed with momentary assessment technology for five consecutive days. Multilevel regression analyses were used to examine moderation of childhood adversity by genetic liability for depression in the prediction of follow-up psychotic experiences.

RESULTS

The effect of childhood adversity was significantly moderated by genetic vulnerability for depression in the model of both follow-up psychotic experiences (SCL-90-R) and follow-up psychotic trait liability (CAPE). The moderation by genetic liability was mediated by depressive experience but not by stress sensitivity.

CONCLUSIONS

Genetic liability for depression may potentiate the pathway from childhood adversity to psychotic-like symptoms through dysfunctional emotional processing of anomalous experiences associated with childhood trauma.

The psychosis continuum in the general population: findings from the São Paulo Epidemiologic Catchment Area Study

The aim of the study was to examine the psychosis continuum in a Latin-American community setting. Data were from the Brazilian São Paulo Epidemiologic Catchment Area Study, a cross-sectional survey conducted in two boroughs of the city of São Paulo. The Composite International Diagnosis Interview (version 1.1) was applied to a probabilistic sample of 1,464 adults, who were interviewed in their household, in order to identify the presence of psychotic symptoms. A subsample was assessed with Schedules for Clinical Assessment in Neuropsychiatry interview. We described the occurrence of psychotic symptoms, categorized into subgroups according to their clinical impact, disability, and help-seeking behavior. The correlation of socio-demographic variables, depressive symptoms, and alcohol and substance use disorders with those psychotic subgroups was analyzed. Polychotomic logistic regression tested the associations between subgroups of psychosis (clinical and subclinical) and the correlates. Of the total sample, 38.0% presented at least one lifetime psychotic symptom, 1.9% met the criteria for an ICD-10 diagnosis of non-affective psychosis, 5.4% presented clinically relevant psychotic symptoms, and 30.7% endorsed clinically non-relevant symptoms. The most common psychotic symptom was delusion with a plausible explanation (in 18.6%). The presence of any psychiatric diagnosis was associated with the presence of psychotic symptoms (OR range, 1.9-8.9). Subclinical psychosis subgroups were found to be associated with the 18-24 year age bracket, chronic depressive mood, and alcohol use disorder. Our results support the concept of a psychosis continuum in Latin-American populations, suggesting that different risk factors influence their manifestation across the continuum.

Subclinical psychosis and depression: co-occurring phenomena that do not predict each other over time

BACKGROUND

The path from subclinical psychotic experiences to clinical disorder is thought to be mediated by the persistence of subclinical psychotic experiences. One of the factors that is likely associated with this persistence is depression. Although commonly viewed as interrelated concepts, the exact relationship between subclinical psychosis and depression is not clear.

METHODS

Cross-lagged path modeling was used to explore the relationship between subclinical psychosis and depression across and over time in an adolescent population seeking assistance for non-psychotic disorders (N=138), measured at four occasions over a two-year period.

RESULTS

Subclinical psychosis and depression were related to each other at every cross-sectional measurement, but did not predict each other over time. Subclinical psychotic experiences and depressive symptom levels were highest at baseline, when participants presented to the clinical service for help. In addition, the relationship between them was also strongest at baseline and decreased significantly over time.

CONCLUSION

The results suggest that psychosis and depression are interrelated phenomena that strongly co-occur in time, but longitudinally, one does not predict change in the other. Both psychopathological dimensions should be addressed when treatment is provided to adolescent help-seekers.

An investigation of the relationship between cortical connectivity and schizotypy in the general population

Recent neuroimaging investigations have identified a relationship between psychotic symptoms in schizophrenia and abnormal brain connectivity. On the basis of the continuum model of psychosis, it was hypothesized that schizotypal traits in healthy control participants would be associated with relatively impaired frontotemporal white matter health as assessed using diffusion tensor imaging. Twenty-one participants (12 women and 9 men aged 18 to 58 years) completed the Schizotypal Personality Questionnaire (SPQ) and underwent diffusion-weighted magnetic resonance imaging scanning as part of a larger study. White matter integrity for the major association fibre tracts was assessed using standard measures of diffusivity, specifically fractional anisotropy (FA) and axial and radial diffusivity. A series of negative binomial regressions yielded significant relationships between reduced FA in seven white matter tracts and increased scores on the SPQ cognitive-perceptual factor. These findings are consistent with research relating brain connectivity to the positive symptoms of schizophrenia, suggesting that the neurobiological bases of schizotypal personality in healthy controls may be analogous to the neurobiological bases of schizophrenia spectrum disorders.

Affective dysregulation and reality distortion: a 10-year prospective study of their association and clinical relevance

Evidence from clinical patient populations indicates that affective dysregulation is strongly associated with reality distortion, suggesting that a process of misassignment of emotional salience may underlie this connection. To examine this in more detail without clinical confounds, affective regulation-reality distortion relationships, and their clinical relevance, were examined in a German prospective cohort community study. A cohort of 2524 adolescents and young adults aged 14-24 years at baseline was examined by experienced psychologists. Presence of psychotic experiences and (hypo)manic and depressive symptoms was assessed at 2 time points (3.5 and up to 10 years after baseline) using the Munich-Composite International Diagnostic Interview. Associations were tested between level of affective dysregulation on the one hand and incidence of psychotic experiences, persistence of these experiences, and psychotic Impairment on the other. Most psychotic experiences occurred in a context of affective dysregulation, and bidirectional dose-response was apparent with greater level of both affective dysregulation and psychotic experiences. Persistence of psychotic experiences was progressively more likely with greater level of (hypo)manic symptoms (odds ratio [OR] trend=1.51, P<.001) and depressive symptoms (OR trend=1.15, P=.012). Similarly, psychotic experiences of clinical relevance were progressively more likely to occur with greater level of affective dysregulation (depressive symptoms: OR trend=1.28, P=.002; (hypo)manic symptoms: OR trend=1.37, P=.036). Correlated genetic liabilities underlying affective and nonaffective psychotic syndromes may be expressed as correlated dimensions in the general population. Also, affective dysregulation may contribute causally to the persistence and clinical relevance of reality distortion, possibly by facilitating a mechanism of aberrant salience attribution.

Can obsessions drive you mad? Longitudinal evidence that obsessive-compulsive symptoms worsen the outcome of early psychotic experiences

OBJECTIVE

Although there is substantial comorbidity between psychotic disorder and obsessive-compulsive disorder (OCD), little is known about how these clinical phenotypes, and their subclinical extended phenotypes, covary and impact on each other over time. This study examined cross-sectional and longitudinal associations between both (extended) phenotypes in the general population.

METHOD

Data were obtained from the three waves of the NEMESIS-study. A representative population sample of 7076 participants were assessed using the composite international diagnostic interview (CIDI) at baseline (T(0)), 1 year later at T(1) and again 2 years later at T(2).

RESULTS

At T(0), a lifetime diagnosis of psychotic disorder was present in 1.5% of the entire sample, in 11.5% of the people with any OC symptom and in 23.0% of individuals diagnosed with OCD. OC symptoms at T(0) predicted incident psychotic symptoms at T(2). Similarly, T(0) psychotic symptoms predicted T(2) OC symptoms. The likelihood of persistence of psychotic symptoms or transition to psychotic disorder was higher if early psychosis was accompanied by co-occurring OC symptoms, but not the other way around.

CONCLUSION

OCD and the psychosis phenotype cluster together and predict each other at (sub)clinical level. The co-occurrence of subclinical OC and psychosis may facilitate the formation of a more 'toxic' form of persistent psychosis.

The 2nd Schizophrenia International Research Society Conference, 10-14 April 2010, Florence, Italy: summaries of oral sessions

The 2nd Schizophrenia International Research Society Conference, was held in Florence, Italy, April 10-15, 2010. Student travel awardees served as rapporteurs of each oral session and focused their summaries on the most significant findings that emerged from each session and the discussions that followed. The following report is a composite of these reviews. It is hoped that it will provide an overview for those who were present, but could not participate in all sessions, and those who did not have the opportunity to attend, but who would be interested in an update on current investigations ongoing in the field of schizophrenia research.

The Netherlands Mental Health Survey and Incidence Study-2 (NEMESIS-2): design and methods

The psychiatric epidemiological population study NEMESIS-2 (Netherlands Mental Health Survey and Incidence Study-2) replicates and expands the first Netherlands Mental Health Survey and Incidence Study (NEMESIS-1) conducted from 1996 to 1999. The main objectives of the new study are to provide up-to-date figures on the prevalence, incidence, course and consequences of mental disorders, and to study trends in mental disorders and service use, with the use of a new sample. New topics not included in NEMESIS-1 were added, e.g. impulse-control disorders, and genetic correlates of mental disorders through gathering DNA from saliva samples. This paper gives an overview of the design of NEMESIS-2, especially of its recently completed first wave. NEMESIS-2 is a prospective study among Dutch-speaking subjects aged 18-64 years from the general Dutch population. Its baseline wave included 6646 subjects. Three waves are planned with three year-intervals between the waves. A multistage, stratified random sampling procedure was applied. The baseline wave of NEMESIS-2 was performed between November 2007 and July 2009. Face-to-face interviews were administered with the Composite International Diagnostic Interview (CIDI) 3.0. The response rate was 65.1%, and 76.4% of the respondents donated saliva. The sample was reasonably nationally representative, but younger subjects were somewhat underrepresented. In conclusion, we were able to build a comprehensive dataset of good quality, permitting several topics to be studied in the future.

Modeling psychopathology structure: a symptom-level analysis of Axis I and II disorders

BACKGROUND

Analyses of co-morbidity patterns among common mental disorders have repeatedly indicated that relationships among disorders can be understood in terms of broad superordinate dimensions. However, these analyses have been based on syndromal-level indicators, which are often heterogeneous, rather than on symptoms, which are presumably more homogeneous.

METHOD

Symptom-level exploratory and confirmatory analyses were used to explore the joint hierarchical organization of Axis I and II psychopathology, using data on 8405 individuals from the 2000 British Psychiatric Morbidity Survey.

RESULTS

Analyses indicated that 20 identified subordinate dimensions of psychopathology could be organized into four broad superordinate dimensions: Internalizing, Externalizing, Thought Disorder, and Pathological Introversion.

CONCLUSIONS

These results extend existing model frameworks 'downward' as well as 'outward', by analyzing symptoms rather than diagnoses, and by integrating symptoms from Axis I and II disorders in a common framework. This model demonstrates the importance of hierarchy in psychopathology structure, comprises replicable features of psychopathology structure, and has important implications for understanding the nature and organization of mental disorders.

Prediction of transition from common adolescent bipolar experiences to bipolar disorder: 10-year study

BACKGROUND

Although (hypo)manic symptoms are common in adolescence, transition to adult bipolar disorder is infrequent.

AIMS

To examine whether the risk of transition to bipolar disorder is conditional on the extent of persistence of subthreshold affective phenotypes.

METHOD

In a 10-year prospective community cohort study of 3021 adolescents and young adults, the association between persistence of affective symptoms over 3 years and the 10-year clinical outcomes of incident DSM-IV (hypo)manic episodes and incident use of mental healthcare was assessed.

RESULTS

Transition to clinical outcome was associated with persistence of symptoms in a dose-dependent manner. Around 30-40% of clinical outcomes could be traced to prior persistence of affective symptoms.

CONCLUSIONS

In a substantial proportion of individuals, onset of clinical bipolar disorder may be seen as the poor outcome of a developmentally common and usually transitory non-clinical bipolar phenotype.

Prevalence and correlates of auditory vocal hallucinations in middle childhood

BACKGROUND

Hearing voices occurs in middle childhood, but little is known about prevalence, aetiology and immediate consequences.

AIMS

To investigate prevalence, developmental risk factors and behavioural correlates of auditory vocal hallucinations in 7- and 8-year-olds.

METHOD

Auditory vocal hallucinations were assessed with the Auditory Vocal Hallucination Rating Scale in 3870 children. Prospectively recorded data on pre- and perinatal complications, early development and current problem behaviour were analysed in children with auditory vocal hallucinations and matched controls.

RESULTS

The 1-year prevalence of auditory vocal hallucinations was 9%, with substantial suffering and problem behaviour reported in 15% of those affected. Prevalence was higher in rural areas but auditory vocal hallucinations were more severe and had greater functional impact in the urban environment. There was little evidence for associations with developmental variables.

CONCLUSIONS

Auditory vocal hallucinations in 7- and 8-year-olds are prevalent but mostly of limited functional impact. Nevertheless, there may be continuity with more severe psychotic outcomes given the serious suffering in a subgroup of children and there is evidence for a poorer prognosis in an urban environment.

Berkson's bias and the mood dimensions of bipolar disorder

In this paper we examined whether manic and depressive dimensions independently contribute to mental health service use and determined the degree of comorbidity between manic and depressive dimensions in individuals with and without mental health service use. If both depressive and manic episodes independently influence help-seeking behaviour, a higher level of comorbidity between these dimensions would be found in clinical as compared to non-clinical samples (i.e. Berkson's Bias). Data were derived from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a prospective epidemiological survey in a representative sample of the Dutch population (N = 7076). Dimensions of depression and mania and mental health service use (MHSU) were assessed with the Composite International Diagnostic Interview (CIDI) at baseline, and prospectively one and three years later. Logistic regression was used to test whether depressive and manic dimensions both had independent effects on mental health service use. The degree of mania-comorbidity given the presence of depressive dimension was assessed as a function of MHSU, both retrospectively and prospectively. Manic and depressive dimensions contributed independently to mental health service use. Mania-comorbidity given the presence of depressive dimension was significantly higher in individuals with mental health service use than in those without, both retrospectively (16.7% versus 7.1%, p = 0.000) and prospectively (10.8% versus 6.6%, p = 0.017). We conclude that the bipolar phenotype consists of manic and depressive dimensions that may be much more loosely associated than (Berkson) biased clinical observations suggest. A dimension-specific approach may be more productive in clarifying the aetiology of mood dysregulation.

Cognition as predictor of current and follow-up depressive symptoms in the general population

OBJECTIVE

Previous studies have reported an association between depression and poor cognitive functioning. Unknown is to what degree such associations are merely state-related or reflect an enduring depression vulnerability. This study examined whether cognitive deficits predict current and/or follow-up (sub)clinical depressive symptoms in the general population.

METHOD

A population-based sample of 569 female twins and 43 of their sisters completed a neuropsychological battery. Cross-sectional and prospective associations between depressive symptoms measured at the subclinical [Symptom Checklist-90 (SCL-90)] and clinical level (Structured Clinical Interview for DSM-IV disorders) and neuropsychological factors (episodic memory and information processing speed) were examined.

RESULTS

Structured Clinical Interview for DSM-IV disorders baseline depressive symptoms were significantly associated with information processing speed but not with episodic memory. Episodic memory was significantly associated with follow-up SCL-90 depressive symptoms.

CONCLUSION

Being depressed is accompanied by slower information processing. Poor memory functioning may be a predictor for the onset of subclinical depressive symptoms.

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.

A systematic review and meta-analysis of the psychosis continuum: evidence for a psychosis proneness-persistence-impairment model of psychotic disorder

A systematic review of all reported incidence and prevalence studies of population rates of subclinical psychotic experiences reveals a median prevalence rate of around 5% and a median incidence rate of around 3%. A meta-analysis of risk factors reveals associations with developmental stage, child and adult social adversity, psychoactive drug use, and also male sex and migrant status. The small difference between prevalence and incidence rates, together with data from follow-up studies, indicates that approximately 75-90% of developmental psychotic experiences are transitory and disappear over time. There is evidence, however, that transitory developmental expression of psychosis (psychosis proneness) may become abnormally persistent (persistence) and subsequently clinically relevant (impairment), depending on the degree of environmental risk the person is additionally exposed to. The psychosis proneness-persistence-impairment model considers genetic background factors impacting on a broadly distributed and transitory population expression of psychosis during development, poor prognosis of which, in terms of persistence and clinical need, is predicted by environmental exposure interacting with genetic risk.

Demographic correlates of psychotic-like experiences in young Australian adults

OBJECTIVE

Psychotic-like experiences (PLE) in the general community are common. The aims of this study were to examine the prevalence and demographic correlates of PLE in young adults.

METHOD

The sample consisted of 2441 subjects aged 18-23 years. Subjects completed the Composite International Diagnostic Interview (CIDI) and the 21-item Peters Delusional Inventory (PDI). Associations between age, gender, hallucinations and delusions were examined using logistic regression.

RESULTS

Both CIDI hallucinations and delusions predicted high scores on the PDI. Younger age was significantly associated with endorsement of CIDI delusions [odds ratio (OR) = 0.66, 95% confidence interval (CI) 0.48-0.92) and with PDI total scores (OR = 0.68, 95% CI 0.55-0.83). Women were significantly more likely to endorse items related to hallucinations (OR = 1.49, 95% CI 1.14-1.95) but not delusions.

CONCLUSION

PLE are common in young adults. The mechanisms underpinning the age and gender gradients in PLE may provide clues to the pathogenesis of psychotic disorders.