The association between adult attachment style and delusional-like experiences in a community sample of women.

Community-based surveys have found that many otherwise well individuals endorse delusional-like experiences (DLEs). There is extensive literature that describes the demographic and psychosocial correlates of DLE; however, we know little about the association between DLE and attachment style. The association between DLEs (assessed by the Peters Delusional Inventory [PDI]) and interpersonal relationship style (as assessed by the Adult Attachment Questionnaire and the Dyadic Adjustment Scale) was examined in 3360 women. When adjusted for the presence of depressive and anxiety symptoms, high scores on the PDI (lowest versus highest quartiles) were associated with a) difficulties in adult attachment style particularly in the discomfort with closeness and preoccupation with relationships subscales and b) conflictual dyadic adjustment (adjusted odds ratios and 95% confidence intervals, 2.43 and 1.94-3.04, 2.50 and 1.99-3.14, and 2.90 and 1.38-6.06, respectively). The association between adult attachment style and DLE provides new clues into the causal pathway underpinning these common experiences.

Anxiety and depressive disorders are associated with delusional-like experiences: a replication study based on a National Survey of Mental Health and Wellbeing.

OBJECTIVES: There is growing evidence that delusional-like experiences (DLE) are associated with common mental disorders. In particular, a National Mental Health Survey conducted in Australia during 2007 reported an association between DLE and both anxiety disorder and major depressive disorder (MDD). However, the previous study did not examine this association with respect to subtypes of anxiety disorder nor with severity of MDD. The aim of this study was to examine the associations between DLE and both anxiety disorder and MDD in more detail based on an independent population sample. DESIGN: Cross-sectional study. SETTING: Subjects were drawn from the Australian Survey of Mental Health and Wellbeing 1997 using a stratified multistage area sampling of persons living in private dwellings in all States and Territories of Australia. PARTICIPANTS: Approximately 13 600 private dwellings were initially selected with one person aged 18 years or older from each dwelling invited to participate. In total, 10 641 individuals participated in the survey. PRIMARY AND SECONDARY OUTCOME MEASURES: The Composite International Diagnostic Interview was used to identify individuals with DLE and Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition (DSM IV) lifetime diagnoses of anxiety disorders and MDD. The influence of various anxiety disorders and MDD on DLE was assessed with logistic regression. RESULTS: Having a lifetime diagnosis of either any anxiety disorder or MDD was significantly associated with the endorsement of DLE. The association was found for each of the main anxiety disorders when examined separately. There was a dose-response relationship between increasing severity of MDD and higher odds of DLE endorsement. CONCLUSIONS: DLE are associated with a wide range of anxiety disorders and are more prevalent in those with MDD. Understanding the relationship between DLE, anxiety disorders and depression may provide insights into shared pathways that underpin both psychotic disorders and common mental disorders.

The association between delusional-like experiences, and tobacco, alcohol or cannabis use: a nationwide population-based survey.

BACKGROUND: Previous population-based studies have found that delusional-like experiences (DLE) are prevalent in the community, and are associated with a wide range of mental health disorders including substance use. The aim of the study was to explore the association between DLE and three commonly used substances--tobacco, alcohol and cannabis. METHODS: Subjects were drawn from the Australian National Survey of Mental Health and Wellbeing 2007. The Composite International Diagnostic Interview was used to identify DLE, common psychiatric disorders, and substance use. We examined the relationship between the variables of interest using logistic regression, adjusting for potential confounding factors. RESULTS: Of 8,773 participants, 8.4% (n=776) subjects endorsed one or more DLE. With respect to tobacco use, compared to nonusers, DLE were more common in those who (a) had daily use, (b) commenced usage aged 15 years or less, and (c) those who smoked heavily (23 or more cigarettes per day). Participants with cannabis use disorders were more likely to endorse DLE; this association was most prominent in those with an onset of 16 years or younger. In contrast, the pattern of association between DLE versus alcohol use or dependence was less consistent, however those with early onset alcohol use disorders were more likely to endorse DLE probe items. CONCLUSIONS: While cannabis use disorders have been previously linked with DLE, our findings linking alcohol and tobacco use and DLE suggest that the influence of these substances on psychosis-related outcomes warrants closer scrutiny in longitudinal prospective studies.

The association between delusional-like experiences and suicidal thoughts and behaviour.

BACKGROUND: Delusional-like experiences (DLEs) are common in the general population. Whilst it is well known that psychotic disorders increase the risk of suicide, it is unclear if DLEs are also associated with suicidal thoughts and behaviour. This study aims to explore these variables in a large population-based sample. METHOD: Participants were drawn from a national survey of mental health (n=8841) in Australia. The Composite International Diagnostic Interview was used to identify DLEs, psychiatric disorders, and information related to suicidal ideation, suicide plan and suicide attempts. We examined the relationship between DLEs and suicidal ideation, plans and attempts using logistic regression, adjusted for a range of potentially confounding variables. RESULTS: 8.4% of subjects endorsed one or more DLEs. 12.9% subjects reported suicidal ideation, 3.8% suicidal plans, and 3.0% a suicide attempt at some point in their lives. Those with any DLE were about two to four times as likely to report suicidal ideation, plans or attempts. There was a dose response relationship between DLEs and endorsement of suicide-related items. CONCLUSIONS: DLEs are common in the general population and appear to be independently associated with suicidal thoughts and behaviour. DLE may provide a marker of vulnerability to suicide, and thus could be of value in future suicide prevention research.

The association between physical health and delusional-like experiences: a general population study.

OBJECTIVE: Delusional-like experiences (DLE) are prevalent in the community. Recent community based studies have found that DLE are more common in those with depression and anxiety disorders, and in those with subclinical symptoms of depression and anxiety. Chronic physical disorders are associated with comorbid depression and anxiety; however, there is a lack of evidence about the association of DLE with common physical conditions. The aim of this study was to explore associations between the common physical disorders and DLE using a large population sample. METHODS: Subjects were drawn from the Australian National Survey of Mental Health and Wellbeing 2007, a national household survey of 8841 residents aged between 16 and 85 years. The presence of DLE, selected common physical disorders and symptoms were assessed using a modified World Mental Health Composite International Diagnostic Interview (CIDI) schedule. We examined the relationship between DLE, and physical health-related variables using logistic regression, with adjustments for potential confounding factors. RESULTS: Of the 8771, 776 (8.4%) subjects positively endorsed one or more DLE. Of the six physical disorders examined, only diabetes and arthritis were significantly associated with the endorsement of DLE. Of the seven broad physical symptoms explored, only hearing problems were consistently associated with DLE. CONCLUSION: Delusional-like experiences are common in the Australian community, and are associated with selected chronic physical disorders and with impaired hearing. The direction of causality between these variables warrants closer research scrutiny.

The association between trauma and delusional-like experiences.

Individuals exposed to childhood trauma are more likely to report delusional-like experiences (DLE). This study examined the association between trauma exposure and DLE in a large community sample, investigating different trauma types and age-at-first-exposure to trauma. Subjects were from the Australian National Survey of Mental Health and Wellbeing 2007. Associations between DLE and (i) exposure to different trauma types and (ii) age-at-first-exposure were assessed using logistic regression with adjustments for potential confounding factors. 8.4% of 8773 subjects reported DLE and almost 75% reported at least one traumatic event. Exposure to a traumatic event was significantly associated with more than twice the odds of delusional-like experiences and exposure to more types of trauma increased the likelihood of DLE in a dose dependent fashion. The majority of the individual trauma items were independently associated with any endorsement of DLE. First exposure of trauma in childhood, adolescence and adulthood was all associated with DLE. Further understanding of biological and cognitive pathways is required to unravel the association between trauma exposure and delusional-like experiences.

The association between family history of mental disorder and delusional-like experiences: a general population study.

Recent studies have indicated that isolated delusional-like experiences (DLE) are common in the general population. Furthermore, there is preliminary evidence to suggest that these experiences are more common in those with a family history of mental disorders. We had the opportunity to explore the association between family history of a wide range of mental disorders and DLE in an Australian general population survey. The Australian National Survey of Mental Health and Wellbeing 2007 examined 8,841 adult community residents. The Composite International Diagnostic Interview was used to generate various DSM-IV lifetime diagnoses and to assess DLE. The participants were asked to report mental disorders in their first-degree relatives. The influence of family history of mental disorders on DLE endorsement was assessed with logistic regression, with adjustments for age, sex, and the presence of comorbid psychiatric diagnoses in the respondents. A family history of anxiety, depression, schizophrenia, bipolar disorder, or alcohol or illicit drug abuse/dependence was each significantly associated with endorsement of DLE, and these associations remained significant when we adjusted for the presence of mental illness in the respondents. When we examined a more restrictive definition of DLE, only a family history of depression and schizophrenia remained significantly associated with DLE. DLE are associated with a family history of a wide range of mental disorders. These findings suggest that familial factors associated with DLE may be shared with a wide range of common mental disorders.

The association between general psychological distress and delusional-like experiences: a large population-based study.

BACKGROUND: Delusional-like experiences (DLE) are prevalent in the community, and are associated with the both clinical and subclinical depression and anxiety. The aim of this study was to explore the association between general psychological distress and DLE adjusting for the presence of psychiatric disorders in a large population-based sample. METHODS: Subjects were drawn from the Australian National Survey of Mental Health and Wellbeing 2007 (n=8841). DLE were assessed using a modified World Mental Health Composite International Diagnostic Interview (CIDI) schedule, and psychological distress was measured using the Kessler-10 (K10) short questionnaire. We examined the relationship between DLE and quartiles of K10 scores using logistic regression, adjusting for depression and anxiety disorders, and other potential confounding factors. The analyses were also repeated in the subgroup of the sample who were free of lifetime clinical diagnoses. RESULTS: Of the participants, 776 (8.4%) endorsed one or more DLE. Individuals with moderate and severe psychological distress were two to three times more likely to endorse DLE. The association remained significant after adjusting for potential confounding factors, and in the subgroup of the population who remained after excluding those who met criteria for lifetime diagnosis for any mental disorder. CONCLUSION: While DLE have traditionally been associated with psychotic disorders, our results suggest that they are associated with non-specific psychological distress in otherwise-well individuals.

Psychotic-like experiences in major depression and anxiety disorders: a population-based survey in young adults.

OBJECTIVE: Population-based surveys have confirmed that psychotic-like experiences are prevalent in the community. However, it is unclear if these experiences are associated with common mental disorders. The aim of this study was to examine the prevalence of psychotic-like experiences in those with affective and anxiety disorders. METHODS: Subjects were drawn from the Mater-University of Queensland Study of Pregnancy. Delusion-like experiences were assessed with the Peters Delusional Inventory (PDI). The Composite International Diagnostic Interview (CIDI) was used to identify individuals with Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) lifetime diagnoses of major depression, anxiety disorder, substance use/dependence, and psychotic disorders. The influence of affective and anxiety disorders on PDI and CIDI psychosis-related items' scores were assessed with logistic regression, with adjustments for age, sex, and the presence of the other comorbid psychiatric diagnoses. RESULTS: Having either a lifetime diagnosis of major depressive disorder or an anxiety disorder was associated with significantly higher PDI total scores (highest vs lowest quartile adjusted odds ratios [ORs] and 95% confidence intervals [CIs] = 4.43, 3.09-6.36; 3.08, 2.26-4.20, respectively). The odds of endorsing any CIDI hallucination or delusion item was increased in those with a major depressive or anxiety disorder. The presence of current anxiety disorder symptoms was significantly associated with PDI score (OR = 5.81, 95% CI = 3.68-9.16). CONCLUSION: While psychotic-like experiences are usually associated with psychotic disorders, individuals with depression and anxiety are also more likely to report these symptoms compared with well individuals. Psychotic-like experiences are associated with a range of common mental disorders.

Association between cannabis use and psychosis-related outcomes using sibling pair analysis in a cohort of young adults.

CONTEXT: Prospective cohort studies have identified an association between cannabis use and later psychosis-related outcomes, but concerns remain about unmeasured confounding variables. The use of sibling pair analysis reduces the influence of unmeasured residual confounding. OBJECTIVE: To explore the association between cannabis use and psychosis-related outcomes. DESIGN: A sibling pair analysis nested within a prospective birth cohort. SETTING: Births at a Brisbane, Australia, hospital. PARTICIPANTS: Three thousand eight hundred one young adults born between 1981 and 1984 as part of the Mater-University Study of Pregnancy. MAIN OUTCOME MEASURES: Cannabis use and 3 psychosis-related outcomes (nonaffective psychosis, hallucinations, and Peters et al Delusions Inventory score) were assessed at the 21-year follow-up. Associations between duration since first cannabis use and psychosis-related outcomes were examined using logistic regression adjusted for sex, age, parental mental illness, and hallucinations at the 14-year follow-up. Within 228 sibling pairs, the association between within-pair differences in duration since first cannabis use and Peters et al Delusions Inventory score was examined with general linear modeling. The potential impact of attrition was examined. RESULTS: Duration since first cannabis use was associated with all 3 psychosis-related outcomes. For those with duration since first cannabis use of 6 or more years, there was a significantly increased risk of (1) nonaffective psychosis (adjusted odds ratio, 2.2; 95% confidence interval, 1.1-4.5), (2) being in the highest quartile of Peters et al Delusions Inventory score (adjusted odds ratio, 4.2; 95% confidence interval, 4.2-5.8), and (3) hallucinations (adjusted odds ratio, 2.8; 95% confidence interval, 1.9-4.1). Within sibling pairs, duration since first cannabis use and higher scores on the Peters et al Delusions Inventory remained significantly associated. CONCLUSIONS: Early cannabis use is associated with psychosis-related outcomes in young adults. The use of sibling pairs reduces the likelihood that unmeasured confounding explains these findings. This study provides further support for the hypothesis that early cannabis use is a risk-modifying factor for psychosis-related outcomes in young adults.

Correlates of delusion-like experiences in a non-psychotic community sample.

OBJECTIVE: Several large population-based studies have reported that otherwise-well individuals endorse items related to delusion-like experiences. The aim of the present study was to examine selected correlates of delusion-like experiences in a sample of non-psychotic individuals. METHOD: Subjects (n=310) were screened with the Diagnostic Interview for Psychosis in order to exclude psychotic disorders. Delusion-like experiences were assessed with the Peters Delusional Inventory (PDI). Non-parametric statistics were used to assess the relationship between total PDI score and a range of demographic (age, sex, migrant status, paternal age), physical (minor physical anomalies) symptom-related variables (hallucinations, awareness of thought disorder) and family history of mental illness. RESULTS: The median (range) PDI score was 4 (0-26), while one-third of the subjects endorsed seven or more items. The presence of a family history of any psychiatric condition was significantly correlated with a higher PDI score. PDI score was significantly positively correlated with endorsement of hallucinations and awareness of thought disorder. PDI was not significantly associated with sex, family history of schizophrenia, paternal age, migrant status nor scores related to minor physical anomalies. There was a trend level association between younger age and higher PDI score. CONCLUSION: Delusion-like experiences are relatively common in non-psychotic individuals. The association with a family history of mental disorders provides clues to the mechanisms underlying the profile of delusion-like experience.

Schizophrenia-like psychosis and aceruloplasminemia.

Schizophrenia-like illnesses occur in a variety of medical and neurological conditions but to date have not been described in association with aceruloplasminemia. Aceruloplasminemia is an autosomal recessive disorder of iron metabolism which leads to iron deposition in the basal ganglia, thalamus, cerebellum and hippocampus and which usually presents in middle age with extrapyramidal symptoms and dementia. We describe a 21-year-old woman on treatment for aceruloplasminemia who presented with schizophrenia-like psychosis and declining function in the absence of neurological signs. Neuropsychological testing showed significant dominant hemisphere deficits. Magnetic resonance imaging showed bilateral iron deposition in the cerebellar dentate nuclei and thalami, frontal atrophy, and periventricular white matter hyperintensities. Functional imaging suggested global hypoperfusion. The clinical, cognitive and imaging findings were not typical for either aceruloplasminemia or schizophrenia alone and the possible relationship between the two disorders is discussed with particular reference to implications for our understanding of schizophrenia.