Background. Although the DSM-IV-TR is organized into discrete disorders, the question of whether a given disorder possesses a dimensional or a categorical latent structure is an empirical one that can be examined using taxometric methods. The objective of this study was to ascertain the latent structure of antisocial personality disorder (ASPD).

Method. Participants were 1146 male offenders incarcerated in state prisons (n=569), or court-ordered to residential drug treatment (n=577). Participants were interviewed using the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II) to assess ASPD symptoms; they also completed the Personality Diagnostic Questionnaire-4 (PDQ-4) ASPD scale. Taxometric analyses were performed to examine whether ASPD is underpinned by a discrete category or a dimensional construct.

Results. Multiple taxometric procedures using two different sets of indicators provided no evidence that ASPD has a taxonic latent structure. Instead, the results were far more consistent with the proposition that ASPD exists on a continuum, regardless of whether it is assessed using a structured interview or a self-report measure.

Conclusions. Evidence that ASPD is dimensional suggests that it is best studied using continuous measures and that dichotomizing individuals into ASPD versus non-ASPD groups will typically result in decreased statistical power. The findings are also consistent with a multifactorial etiology for ASPD and with recent attempts to conceptualize ASPD within the framework of extant dimensional models of personality.

Background. Previous psychosocial stress research, contemporary cognitive models, and new cognitive behavioural treatments for psychosis converge in suggesting that stressful events influence the content of psychotic experiences. In this paper we test whether the attributes of stressful events preceding the initial onset of psychosis are associated with core themes of the illness.

Method. Forty-one people who had experienced a first episode of psychosis were assessed on the attributes of stressful events occurring in the year before onset, the themes (persecutory, depressive, and grandiose) associated with their delusions and the content of their auditory hallucinations.

Results. Principal component analysis yielded four components accounting for 72% of the variance. As hypothesized, intrusive events were associated with the development of delusions with persecutory themes. Grandiose delusions were negatively associated with loss events. Depressive delusions appear to be associated with danger events rather than loss events.

Conclusion. There are links between stressful event attributes and core psychotic themes at first-episode psychosis. This has implications for theoretical models of, and early psychological intervention for, psychosis.

Background. The role of physical illness and life problems in contributing to suicide in older people is potentially important with regard to suicide prevention.

Method. The aim of the study was to determine the life problems other than psychiatric illness contributing to suicide in older people. Semi-structured psychological autopsy interviews, covering life problems and physical illness prior to death, were conducted with informants for 100 people aged 60 years old and over who died through suicide in five English counties. Interviews were completed with informants for 54 age- and sex-matched control subjects who died through natural causes.

Results. The three most frequent life problems associated with suicide were physical illness, interpersonal problems, and bereavement. Physical health problems were present in 82% and felt to be contributory to death in 62%. Pain, breathlessness and functional limitation were the most frequent symptoms. Interpersonal problems were present in 55% of the sample and contributory in 31%. The corresponding figures for bereavement-related problems were 47% and 25%. In the case-control analysis, the problems found to be risk factors for suicide were problems related to a bereavement over 1 year before death (OR 3·5, 95% CI 1·2–10·6), and problems with accommodation (OR 5·0, 95% CI 1·1–22·8), finances (p=0·01), and retirement (p=0·02).

Conclusion. Physical illness, interpersonal problems and bereavement are commonly associated with suicide in older people, but financial, accommodation, retirement and long- term bereavement-related problems may be more specific risk factors.

Background. An ecological analysis found that the docosahexaenoic acid content in mother's milk and seafood intake were inversely correlated with postpartum depression. This prospective study investigated the relationship of consumption of selected high-fat foods and specific types of fatty acids with the risk of postpartum depression.

Method. The subjects were 865 Japanese women. Dietary data were obtained from a self-administered diet history questionnaire during pregnancy. The Edinburgh Postnatal Depression Scale (EPDS) was used for the evaluation of postpartum depression. Adjustment was made for age, gestation, parity, cigarette smoking, family structure, family income, education, changes in diet in the previous month, season when data at baseline were collected, body mass index, time of delivery before the second survey, medical problems in pregnancy, baby's sex and baby's birthweight.

Results. The percentage of women with high depression scores was 14·0%. No evident dose–response associations were observed between intake of fish, meat, eggs, dairy products, total fat, saturated fatty acids, monounsaturated fatty acids, n-3 polyunsaturated fatty acids, n-6 polyunsaturated fatty acids, linoleic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid or docosahexaenoic acid and the ratio of n-3 to n-6 polyunsaturated fatty acids and the risk of postpartum depression. However, there was an inverted J-shaped relationship between intake of n-3 polyunsaturated fatty acids and docosahexaenoic acid and the risk of postpartum depression.

Conclusions. This study failed to substantiate a clear inverse relationship between fish and n-3 polyunsaturated fatty acid intake and postpartum depression. Further investigations are needed to determine whether fish and n-3 polyunsaturated fatty acid consumption is preventive against postpartum depression.

Background. We examined whether there are genetic influences on nicotine withdrawal, and whether there are genetic factors specific to nicotine withdrawal, after controlling for factors responsible for risk of progression beyond experimentation with cigarettes and for quantity smoked (average number of cigarettes per day at peak lifetime use).

Method. Epidemiologic and genetic analyses were conducted using telephone diagnostic interview data from young adult Australian twins reporting any cigarette use (3026 women, 2553 men; mean age 30 years).

Results. Genetic analysis of the eight symptoms of DSM-IV nicotine withdrawal suggests heritability is intermediate for most symptoms (26–43%), and similar in men and women. The exceptions were depressed mood upon withdrawal, which had stronger additive genetic influences in men (53%) compared to women (29%), and decreased heart rate, which had low heritability (9%). Although prevalence rates were substantially lower for DSM-IV nicotine withdrawal syndrome (15·9%), which requires impairment, than for the DSM-IV nicotine dependence withdrawal criterion (43·6%), heritability was similar for both measures: as high as 47%. Genetic modeling of smoking more than 1 or 2 cigarettes lifetime (‘progression’), quantity smoked and nicotine withdrawal found significant genetic overlap across all three components of nicotine use/dependence (genetic correlations=0·53–0·76). Controlling for factors associated with risk of cigarette smoking beyond experimentation and quantity smoked, evidence for genetic influences specific to nicotine withdrawal (up to 23% of total variance) remained.

Conclusions. Our results suggest that at least some individuals become ‘hooked’ or progress in the smoking habit, in part, because of a vulnerability to nicotine withdrawal.

Background. Borderline personality disorder (BPD) is often co-morbid with major depression and may complicate its treatment. We were interested in differences in genetic and developmental risk factors between depressed patients with or without a co-morbid BPD.

Method. Out-patients with major depressive disorder were recruited for two treatment trials. Assessment of depressed patients included the assessment of personality disorders, developmental risk factors and DNA samples for genetic analyses.

Results. In each study there was a significant association between the 9-repeat allele of the dopamine transporter (DAT1) and BPD, with odds ratios (OR) >3 and p[les ]0·02. This association remained significant when developmental risk factors for BPD (childhood abuse and neglect and borderline temperament) were also included in the analyses. The OR was even larger in the depressed patients aged [ges ]35 years (OR 9·31, p=0·005).

Conclusion. This replicated association in depressed patients between the 9-repeat allele of DAT1 and BPD may provide clues to understanding the neurobiology of BPD. The finding that the association is larger in the older depressed patients, suggests that the 9-repeat allele may be associated with a poorer prognosis BPD, rather than a young adult limited variant of BPD.

Background. We sought to develop a refined measure of eight personality traits or constructs observed in those who develop depression. We report the psychometric properties of the derived Temperament and Personality (T&P) questionnaire, as well as a pilot study examining its capacity to differentiate over-represented personality traits in those with depression.

Method. The factor structure of the T&P measure was examined in a general practice sample of 529 subjects. We imposed a range of factorial solutions to determine how higher-order molar constructs arborized to eight lower-order constructs. Scale scores generated at each derived tier were contrasted for 52 out-patients with major depression and control subjects from the general practice sample to pursue over-represented personality constructs, and to clarify if an optimal number of constructs could be identified.

Results. In the factor analysis, some 90% of the items loaded on their a priori construct. The questionnaire showed high internal consistency, test–retest reliability and minimal sensitivity to mood state effects. Analyses rejected the hypothesis that risk to depression might be generally affected by individuals merely scoring high on all ‘normal’ personality styles, whether higher-order or lower-order traits.

Conclusions. Findings suggest that, while identified constructs linked well with the widely accepted theoretical model of personality (the Five Factor Model) at one tier, such a fixed model may be too inflexible. We therefore detail potential advantages to using a multi-tiered model of personality traits in application studies.

Background. We describe the development, reliability and applications of the Diagnostic Interview for Psychoses (DIP), a comprehensive interview schedule for psychotic disorders.

Method. The DIP is intended for use by interviewers with a clinical background and was designed to occupy the middle ground between fully structured, lay-administered schedules, and semi-structured, psychiatrist-administered interviews. It encompasses four main domains: (a) demographic data; (b) social functioning and disability; (c) a diagnostic module comprising symptoms, signs and past history ratings; and (d) patterns of service utilization and patient-perceived need for services. It generates diagnoses according to several sets of criteria using the OPCRIT computerized diagnostic algorithm and can be administered either on-screen or in a hard-copy format.

Results. The DIP proved easy to use and was well accepted in the field. For the diagnostic module, inter-rater reliability was assessed on 20 cases rated by 24 clinicians: good reliability was demonstrated for both ICD-10 and DSM-III-R diagnoses. Seven cases were interviewed 2–11 weeks apart to determine test–retest reliability, with pairwise agreement of 0·8–1·0 for most items. Diagnostic validity was assessed in 10 cases, interviewed with the DIP and using the SCAN as ‘gold standard’: in nine cases clinical diagnoses were in agreement.

Conclusions. The DIP is suitable for use in large-scale epidemiological studies of psychotic disorders, as well as in smaller studies where time is at a premium. While the diagnostic module stands on its own, the full DIP schedule, covering demography, social functioning and service utilization makes it a versatile multi-purpose tool.

Background. The relative contribution of psychosocial and clinical risk factors to suicide among Chinese populations is an important issue. In Hong Kong, this issue requires vigorous examination in light of a 50% increase in suicide rate between 1997 and 2003.

Method. Using a case-control psychological autopsy method, 150 suicide deceased were compared with 150 living controls matched by age and gender. Semi-structured interviews were conducted with the next-of-kin of the subjects. Data were collected on a wide range of potential risk and protective factors, including demographic, life event, clinical and psychological variables. The relative contribution of these factors towards suicide was examined in a multiple logistic regression model.

Results. Six factors were found to significantly and independently contribute to suicide: unemployment, indebtedness, being single, social support, psychiatric illness, and history of past attempts.

Conclusions. Both psychosocial and clinical factors are important in suicides in Hong Kong. They seem to have mediated suicide risk independently. In addition, socio-economic adversities seem to have played a relatively important role in the increasing suicide rate in Hong Kong.

Background. Apart from individuals with clinical psychosis, community surveys have shown that many otherwise well individuals endorse items designed to identify psychosis. The aim of this study was to characterize the demographic correlates of individuals who endorse psychosis screening items in a large general community sample.

Method. The National Survey of Mental Health and Wellbeing interviewed 10641 individuals living in private dwellings in Australia. As part of a diagnostic interview (the CIDI), respondents were asked between three and six items originally designed to screen for potential psychosis. We examined the impact of selected demographic variables on endorsement of these items including sex, age, marital status, migrant status, urban/rural status, employment, education, and socio-economic status.

Results. An estimated 11·7% of the Australian population endorsed at least one psychosis-screening item. Significantly higher endorsement was associated with younger age, migrants from non-English-speaking backgrounds, those who had never married or who were divorced/separated or unemployed, those living in urban regions and those from the lowest socio-economic levels.

Conclusions. Many of the correlates of endorsement of psychosis-screen items are also associated with psychosis. Unravelling the factors that contribute to this broader non-clinical phenotype will aid our understanding of psychosis.

Background. Verbal declarative memory is a core deficit in schizophrenia patients, seen to a lesser extent in unaffected biological relatives. Neuroimaging studies suggest volumetric differences and aberrant function in prefrontal and temporal regions in schizophrenia patients compared to controls. These deficits are also reflected in the small number of similar investigations in unaffected biological relatives. However, it is unclear the extent to which dysfunction is genetically mediated or a feature of the established illness.

Method. Event-related blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was used to measure brain activation in 68 biological relatives of schizophrenia patients (of whom 27 experienced transient or isolated psychotic symptoms) and 21 controls during verbal classification and recognition.

Results. During word classification, the high-risk group showed a greater response relative to controls in the right inferior frontal gyrus. During correct recognition (relative to correct rejection), the high-risk group showed significantly greater response relative to controls in the right cerebellum. When the high-risk group was split into those with (HR+) and without (HR−) psychotic symptoms, the increased response in the right inferior frontal gyrus was only seen when the HR+ were compared to controls. The greater cerebellar response was seen when both HR groups were compared to controls.

Conclusions. Activation increases in the right inferior frontal gyrus and cerebellum in high-risk subjects compared to controls during a relatively low-load memory task are likely to represent compensation for genetically mediated abnormalities. This is consistent with a leftward shift of the inverted ‘U’ load–response model of cognitive function in schizophrenia.

Background. The question of whether unipolar clinical depression differs categorically from limited depressive complaints has important implications for the disorder's assessment, treatment and research. This crucial issue has proven difficult to resolve, in part because many studies to date have relied on self-report measures or on clinically homogeneous samples. We therefore applied Meehl's taxometric method to a large, clinically heterogeneous sample, and examined the latent structure of depressive episodes using both self-report and structured clinical interview data.

Method. Data were derived from the Oregon Adolescent Depression Project, a large longitudinal community study. All analyses involved more than 1400 participants. MAXEIG (MAXimum EIGenvalue) and base rate estimation were performed separately for Beck Depression Inventory (BDI) items and for DSM-IV-based major depressive episode (MDE) symptoms.

Results. MAXEIG analyses of the BDI and MDE indicator sets appeared to converge on a taxonic structure for unipolar depression. Base rate estimates overall implied a latent depressive episode class that occurs more frequently than diagnosable MDEs but less frequently than persistent depressed or anhedonic mood.

Conclusions. These findings provide tentative support for a categorical conceptualization and make it very clear that the continuity controversy regarding unipolar depression has not yet been decided in favor of dimensionality. To reconcile the conflicting reports to date, several data analytic and sampling issues need to be explored systematically.

Background. Effective internet-based programs for depression usually incorporate a component that provides telephone or email contact. Open access websites, without such contact, show high rates of attrition and poorer outcomes. The present study was designed as an exploratory investigation of the parameters that influence the effectiveness and retention of users on open access websites. We investigated whether brief cognitive behaviour therapy (CBT) was as effective as an extended version, whether add-on components of behaviour therapy or stress management contributed to positive outcomes, and whether longer programs were associated with greater attrition.

Method. An online randomized controlled trial (RCT) was conducted between 13 January 2005 and 26 May 2005 (19 weeks). A total of 2794 registrants (1846 women and 948 men; median age category 35–44 years) with elevated scores on the Goldberg Depression Scale of 5·96 (S.D.=2·09) elected online to be randomized to one of six versions of a CBT website. The versions were compiled consisting of various components of brief CBT, extended CBT, behaviour strategies, stress management and problem solving.

Results. A total of 20·4% of participants completed the assigned intervention. The interaction of measurement occasion and treatment version was significant [F(13,131)=2·20, p=0·01]. A single module of brief introductory CBT was not effective in reducing depression symptoms. However, extended CBT with or without the addition of behaviour strategies resulted in the reduction of depression.

Conclusions. Brief CBT-based interventions are not as effective as extended interventions. However, longer programs are associated with higher rates of dropout.

Background. Patients diagnosed with schizophrenia consistently demonstrate impairment in memory acquisition. However, no empirical consensus has been achieved on whether or not patients are more prone to produce false memories.

Method. A visual variant of the Deese–Roediger–McDermott (DRM) paradigm was administered to 35 schizophrenia patients and 34 healthy controls. Recognition and recognition confidence were later tested for studied and lure items. Strong contextual cues at recognition encouraged adoption of a gist-based retrieval strategy, which was predicted to elicit over-confidence in errors and increase the false memory rate in patients.

Results. Patients were significantly impaired on true item recognition but did not display more false memories than healthy subjects. As predicted from prior findings by our group, patients were more confident than controls for lure items, while being at the same time under-confident for studied items (reduced confidence gap).

Conclusions. Although patients did not produce more false memories than controls, such errors were made with higher confidence relative to controls. The decreased confidence gap in patients is thought to stem from a gist-based recollection strategy, whereby little evidence suffices to make a strong judgment.

Background. Although many studies have reported impairments of neurocognitive performance in patients with anorexia nervosa (AN), these have involved a wide range of assessment methods and some findings are inconsistent.

Method. Twenty-five female in-patients with a DSM-IV diagnosis of AN, identified from three units specializing in the treatment of eating disorders, volunteered for the study. Twenty-five non-clinical control subjects were recruited, matched for age, gender and estimated IQ. Subjects were assessed with a range of computer-administered neurocognitive tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB), which has been validated in many studies of neuropsychiatric disorders.

Results. The patient group showed significant but moderate impairments (i.e. less than one standard deviation below the mean performance of the control group) on tests of spatial recognition memory, a planning task and rapid visual information processing, while a subgroup of patients (n=14) showed greater degrees of impairments on at least one of these tests. The degrees of impairments did not correlate with body mass index (BMI). No impairments were observed on tests of spatial span, pattern recognition memory, spatial working memory, matching-to-sample, paired associates learning and set-shifting.

Conclusions. The findings, in relation to a mean BMI of 15·3, are compatible with, in general, subtle impairments in neurocognition in AN. However, in those patients with relatively severe degrees of impairments, these may have adverse effects on complex tasks of social and occupational functioning. Further research is needed on the nature of relevant causal mechanisms, including the effects of potentially confounding variables.

Background. Exploration of the degree to which perceived chronic stress is heritable is important as these self-reports have been linked to stress-related health outcomes. The aims of this study were to estimate whether perceived stress is a heritable condition and to assess whether heritability estimates vary between subjective stress reactivity and stress related to external demands.

Method. A sample of 103 monozygotic and 77 dizygotic twin pairs completed three questionnaires designed to measure perceived stress: the Perceived Stress Scale (PSS), the Measure for the Assessment of Stress Susceptibility (MESA) and the Trier Inventory for the Assessment of Chronic Stress (TICS). The TICS assesses the frequency of stressful experiences on six scales, the MESA assesses subjective stress reactivity, and the PSS takes both factors into account.

Results. A multivariate model-fitting procedure revealed that a model with common additive genetic and shared environmental factors best fit the eight scales (PSS, MESA, six TICS scales). Heritabilities for the best-fitting model varied between 5% and 45%, depending on the scale.

Conclusions. The present data suggest that perceived stress is in part heritable, that nearly half of the covariance between stress scales is due to genetic factors, and that heritability estimates vary considerably, depending on the questionnaire. Beyond methodological considerations that pertain to the validity of the questionnaires, these data suggest that studies assessing the heritability of perceived chronic stress should take the specific questionnaire focus into account.

Background. The ‘odd’ or ‘Cluster A’ personality disorders (PDs) – paranoid, schizoid and schizotypal PDs – were created in DSM-III with little empirical foundation. We have examined the relationship between the genetic and environmental risk factors for dimensional representations of these three personality disorders.

Method. These personality disorders were assessed using the Structured Interview for DSM-IV Personality (SIDP-IV) in 1386 young adult twin pairs from the Norwegian Institute of Public Health Twin Panel. Using Mx, a single-factor independent pathway twin model was fitted to the number of endorsed criteria for the three disorders.

Results. The best-fit model included genetic and unique environmental common factors and genetic and unique environmental effects specific to each personality disorder. Total heritability was modest for these personality disorders and ranged from 21% to 28%. Loadings on the common genetic and unique environmental factors were substantially higher for schizotypal than for paranoid or schizoid PD. The proportion of genetic liability shared with all Cluster A disorders was estimated at 100, 43 and 26% respectively for schizotypal, paranoid and schizoid PDs.

Conclusion. In support of the validity of the Cluster A construct, dimensional representations of schizotypal, paranoid and schizoid PD are all modestly heritable and share a portion of their genetic and environmental risk factors. No evidence was found for shared environmental or sex effects for these PDs. Schizotypal PD most closely reflects the genetic and environmental liability common to all three Cluster A disorders. These results should be interpreted in the context of the limited power of this sample.

Background. To evaluate the longitudinal course of psychiatric disorders in children of parents with panic disorder (PD) and major depression (MD) as they transition through the period of risk from childhood into adolescence.

Method. Over a 5-year follow-up, we compared psychiatric disorders in four groups of children: (1) offspring of parents with PD plus MD (n=136); (2) offspring of parents with PD without MD (n=27); (3) offspring of parents with MD but without PD (n=53); and (4) offspring of non-PD non-MD parents (n=103).

Results. Parental PD was significantly associated with increased risk for anxiety disorders, irrespective of parental MD. Parental MD was associated with increased risk for MD, disruptive behavior disorders, and deficits in psychosocial functioning, irrespective of parental PD.

Conclusions. These longitudinal findings confirm and extend previous cross-sectional results documenting significant associations between PD and MD in parents and patterns of psychopathology and dysfunction in their offspring.

Background. Gender differences in the prevalence of post-traumatic stress disorder were examined by analysing discrepancies between the DSM-IV and ICD-10 diagnostic systems.

Method. Data from the Australian National Survey of Mental Health and Well-Being (n=10641) were analysed at the diagnostic, criterion and symptom level for DSM-IV and ICD-10 PTSD for males versus females.

Results. While there was a significant gender difference in the prevalence of PTSD for ICD-10, no such difference was found for DSM-IV. The pattern of gender difference at the diagnostic level was mirrored in the pattern of gender differences at the criterion level for both DSM-IV and ICD-10. Females only endorsed three symptoms at a significantly higher rate than males. For all other symptoms, endorsement was equal. This apparently small gender difference at the symptom level was sufficient to cause the gender difference at the diagnostic level for ICD-10, but not DSM-IV because of the different manner in which symptoms are configured into criteria in each of the diagnostic systems.

Conclusions. Gender differences in ICD-10 PTSD but not in DSM PTSD diagnoses are attributable in this study to different patterns of endorsement of symptoms by males and females. Possible reasons for the differential endorsement of symptoms and implications for the use of epidemiological instruments are discussed.

Background. A recent meta-analysis provides evidence that generalized anxiety disorder (GAD) is familial. However, two of the key studies relied on subjects who were self-selected or recruited from the clinic setting, thereby limiting generalizability.

Method. We conducted a family study of GAD in which probands and controls came from a community sample originally enrolled in a prevalence study in Edmonton, Canada. One hundred and sixty probands, 764 controls and 2386 first-degree relatives (FDRs) were interviewed using the Diagnostic Interview Schedule (DIS); lifetime diagnoses were made according to DSM-III criteria without exclusions. Logistic regression analysis was performed with GAD (in a proband) as the ‘exposure’, and GAD in an FDR as the ‘outcome’. Several analytic strategies were used to control for potential confounding by major depressive disorder (MDD) and several anxiety disorders (panic disorder, phobic disorders, obsessive–compulsive disorder, and post-traumatic stress disorder).

Results. The odds ratios for the association between GAD in a proband and GAD in an FDR were in the range 1·4–1·8 when the entire FDR sample was analysed, and in the range 2·1–2·8 when we restricted to FDRs who were children of probands and controls.

Conclusion. In the community setting, GAD exhibits mild to moderate familial aggregation.