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Biomedical subjects

Assen Jablensky

Publications and source records attributed to Assen Jablensky.

At least 19 recordsLinked to original sources
PubMed2006

Modifiable risk factors for hospitalization among people with psychosis: evidence from the National Study of Low Prevalence (Psychotic) Disorders.

OBJECTIVE: Relatively little has been published on dynamic, that is, modifiable, as opposed to static risk factors for hospitalization in the research literature on risk factors for hospitalization in serious mental illness. The aim of this study was to develop a model to determine modifiable predictors of hospitalization using data from the Australian National Study of Low Prevalence (Psychotic) Disorders. METHOD: The Study of Low Prevalence Disorders used a two-phase design to estimate the prevalence of psychoses and identify characteristics of people with psychotic illness. This paper compares people hospitalized at the time of census and those using outpatient services. Logistic regression was used to examine the relative impact of dynamic characteristics including service utilization, symptom profile and risky behaviours on a base model for risk of hospitalization. RESULTS: In the base model, course of disorder and age but not type of psychosis were significantly associated with hospitalization. Among symptoms, delusions (but not hallucinations) and negative symptoms significantly increased the odds of hospitalization. Service utilization, especially case management, reduced the odds significantly and substantially. Results for risky behaviours (e.g. substance abuse, offending) were ambiguous. CONCLUSIONS: The results highlight the impact of dynamic factors, particularly case management, over and above static factors in reducing the risk of hospitalization in psychosis, and point to a potential for targeted interventions to avert some of the burden, both emotional and financial, associated with the hospitalization of people with psychotic disorders. These findings have important clinical and policy implications.

Adult↗
PubMed2005

Genomewide scan and fine-mapping linkage studies in four European samples with bipolar affective disorder suggest a new susceptibility locus on chromosome 1p35-p36 and provides further evidence of loci on chromosome 4q31 and 6q24.

We present the findings of a large linkage study of bipolar affective disorder (BPAD) that involved genomewide analysis of 52 families (448 genotyped individuals) of Spanish, Romany, and Bulgarian descent and further fine mapping of the 1p34-p36, 4q28-q31, and 6q15-q24 regions. An additional sample of 56 German families (280 individuals) was included for this fine-mapping step. The highest nonparametric linkage scores obtained in the fine mapping were 5.49 for 4q31 and 4.87 for 6q24 in the Romany families and 3.97 for 1p35-p36 in the Spanish sample. MOD-score (LOD scores maximized over genetic model parameters) analysis provided significant evidence of linkage to 4q31 and at least borderline significance for the 1p and 6q regions. On the basis of these results and previous positive research findings, 4q31 and 6q24 should now be considered confirmed BPAD susceptibility loci, and 1p35-p36 is proposed as a new putative locus that requires confirmation in replication studies.

Bipolar Disorder↗
PubMed2005

Schizotypy and mixed-handedness revisited.

Although some previous studies assert that an association between schizotypy and loss of hand dominance is well established, the prevailing use of student populations, small effect sizes and arbitrariness of handedness classification suggest that this tentative association merits further investigation. The association of schizotypy and loss of hand dominance was examined using four samples. The first comprised 353 randomly selected individuals from the general community, the second comprised 131 screened volunteers participating as control subjects in a family study of schizophrenia, the third included 97 full siblings of schizophrenia patients, and the fourth consisted of 176 schizophrenia patients from the same study. The samples of screened volunteers and nonpsychotic siblings were used to replicate results from the community sample and to test the hypothesis that an increase in genetic liability is related to the association of schizotypal traits and mixed handedness. The results demonstrated that mixed handedness and schizotypy traits were unrelated in the representative sample from the community. This finding was replicated in the sample of screened volunteers, while siblings of schizophrenia patients showed a trend in the direction of the hypothesised relationship. In contrast, there was an expected significant but low in magnitude association between loss of hand dominance and the Schizotypal Personality Questionnaire factor of Cognitive Perceptual Dysfunction in schizophrenia patients.

Adolescent↗
PubMed2005

Genetic evidence for a distinct subtype of schizophrenia characterized by pervasive cognitive deficit.

A novel phenotyping strategy in schizophrenia, targeting different neurocognitive domains, neurobehavioral features, and selected personality traits, has allowed us to identify a homogeneous familial subtype of the disease, characterized by pervasive neurocognitive deficit. Our genome scan data indicate that this subtype, which accounts for up to 50% of our sample, has a distinct genetic basis and explains linkage to chromosome 6p24 reported previously. If representative of other populations, the ratio of schizophrenia subtypes observed in our families could have a profound impact on sample heterogeneity and on the power of genetic studies to detect linkage and association. Our proposed abbreviated battery of tests should facilitate phenotype characterization for future genetic analyses and allow a focus on a crisply defined schizophrenia subtype, thus promoting a more informed search for susceptibility genes.

Attention↗
PubMed2005

Dimensions of intelligence in schizophrenia: evidence from patients with preserved, deteriorated and compromised intellect.

There is a growing literature describing a subgroup of "high-functioning" people with schizophrenia who show preserved intellectual ability (IQ). A detailed characterisation of the cognitive abilities of this group may be important in targeting appropriate treatment, management and services for patients with schizophrenia. It is a widely held belief that variation in cognitive processing speed is the basis of individual differences in intelligence. The main objective of this study was to identify subgroups of schizophrenia patients with preserved (N=45), deteriorated (N=47) and compromised (N=17) intellect in order to study whether these subgroups differ in specific cognitive abilities (e.g. executive functions) or in general cognitive processing speed, as measured with an inspection time (IT) task. The patients who displayed an average estimated premorbid IQ, with no evidence of IQ decline (premorbid-current IQ difference <10 points), were found to show better performance on measures of executive function (continuous performance task, verbal fluency) compared with patients in the deteriorated and compromised subgroups. Nevertheless, this represented significantly impaired performance relative to healthy controls. In contrast, the average inspection times of patients with preserved IQ were as slow as those obtained in the deteriorated or compromised groups, indicating that high functioning patients are impaired in terms of cognitive processing speed. Furthermore, the average IT for all schizophrenia groups was significantly slower than that of healthy controls. These findings suggest that high functioning patients with schizophrenia exhibit enduring cognitive difficulties that may impact on their ability to benefit from rehabilitation interventions.

Adolescent↗
PubMed2005

Psychiatric out-patients seen once only in South Verona and Western Australia: a comparative case-register study.

OBJECTIVE: This study examined variables associated with having a once-only contact with the out-patient department of two community mental health services in Italy and Australia. METHOD: Two 8-year cohorts of patients, who had a new episode of care with out-patient psychiatric departments in South Verona and in Western Australia, were followed-up for 3 months after the first contact, to identify those patients who had no further contact with services. Potential determinants of once-only contact were analysed. RESULTS: Thirty percent of new episodes of care for persons who met the inclusion criteria of the study were once-only contacts with the service in South Verona. In Western Australia, the figure was 24%. Moreover, the proportion of once-only contact patients has increased over time in South Verona whereas, in Western Australia, it has remained stable. In Western Australia, once-only contact patients were younger whereas in South Verona they tended to be older. At both research sites, patients who had a once-only contact were more likely to be male and to have a less severe mental illness. CONCLUSIONS: The results of this study suggest that only clinical characteristics were significant determinants of this pattern of contact with services consistently at both sites: the less severe the patient's diagnosis, the more likely the patient is to have a once-only contact. This may well indicate good screening at the initial point of contact by both sets of mental health service providers. Prospective studies are necessary to clarify the problem of 'once-only contact' and to organize a proper psychiatric care.

Adolescent↗
PubMed2005

Boundaries of mental disorders.

PURPOSE OF REVIEW: This article reviews the problem of 'boundaries' in psychopathology and its conceptualization in the diagnostic classification of psychiatric disorders. RECENT FINDINGS: A modest number of publications in 2004-2005 contribute concepts, methods and data relevant to several aspects of the problem: scientific 'facts' versus value attribution in the definition of mental disorders; the problem of comorbidity between diagnostic entities; the spurious dichotomy between categorical versus dimensional approaches to diagnosis and classification; and the distinction between validity and pragmatic utility. SUMMARY: The relative paucity of research explicitly addressing these issues should be a reason for concern in the debate leading up to the next revisions of the International Classification of Diseases and the Diagnostic and Statistical Manual of Mental Disorders.

Journal Article↗
PubMed2005

Laterality phenotypes in patients with schizophrenia, their siblings and controls: associations with clinical and cognitive variables.

BACKGROUND: Various behavioural indices of brain lateralisation significantly intercorrelate, but current research in this area still focuses on single behavioural asymmetries, such as handedness. AIMS: To describe a novel approach, which simultaneously integrates various laterality indices and delineates complex phenotypes. METHOD: Grade of membership analysis was used to describe latent, complex lateralisation phenotypes in patients with schizophrenia (n=157), their siblings (n=74) and controls (n=77). The indices used were asymmetries of eye, foot and hand; hand motor proficiency; and handedness of patient's first-degree relatives. RESULTS: Three distinct pure types of lateralisation ('right', 'left' and 'mixed') were evident in patients compared with two ('right' and 'left') in siblings and controls. The 'mixed' type in patients featured absence of eye and foot lateralisation and presence of familial sinistrality, despite a right-hand dominance for writing. Patients with schizophrenia expressing the 'left' phenotype had a more severe course of illness, significantly increased scores on two schizotypy factors and poorer neurocognitive performance. The pure types in the siblings were similar to those in healthy controls. CONCLUSIONS: The findings suggest that a leftward reversal, rather than a reduction in lateralisation, is associated with clinical severity and neurocognitive deficits in patients with schizophrenia.

Adolescent↗
PubMed2004

Demographic and clinical correlates of comorbid substance use disorders in psychosis: multivariate analyses from an epidemiological sample.

BACKGROUND: While there has been substantial research examining the correlates of comorbid substance abuse in psychotic disorders, it has been difficult to tease apart the relative importance of individual variables. Multivariate analyses are required, in which the relative contributions of risk factors to specific forms of substance misuse are examined, while taking into account the effects of other important correlates. METHODS: This study used multivariate correlates of several forms of comorbid substance misuse in a large epidemiological sample of 852 Australians with DSM-III-R-diagnosed psychoses. RESULTS: Multiple substance use was common and equally prevalent in nonaffective and affective psychoses. The most consistent correlate across the substance use disorders was male sex. Younger age groups were more likely to report the use of illegal drugs, while alcohol misuse was not associated with age. Side effects secondary to medication were associated with the misuse of cannabis and multiple substances, but not alcohol. Lower educational attainment was associated with cannabis misuse but not other forms of substance abuse. CONCLUSION: The profile of substance misuse in psychosis shows clinical and demographic gradients that can inform treatment and preventive research.

Adolescent↗
PubMed2004

A novel mouse Chr5 locus Diht controls dopamine-induced hypothermia.

Mice of the strain C3H.PRI-Flv(r), carrying genetically determined resistance to flaviviruses, have been shown to be more sensitive to the hypothermic effect of dopamine than congenic flavivirus-susceptible C3H/HeJARC mice. In the current study, the greater sensitivity to dopamine-induced hypothermia observed in flavivirus-resistant mice was shown to be dose-dependent, with strain differences being the most prominent at a moderate dose of apomorphine (1 mg/kg). In addition, hypothermic responses to apomorphine were shown to be under developmental regulation; aging increased the potency of apomorphine-induced hypothermia and abrogated strain and sex differences observed in young mice. Linkage analysis of mouse strain-dependent coinheritance between flavivirus resistance and greater sensitivity to the hypothermic effect of dopamine was performed using two genetically unrelated flavivirus-susceptible and two highly congenic flavivirus-resistant mouse strains in parallel with C3H.PRI-Flv(r)-and C3H/HeJARC reference strains. This study has revealed a clear segregation between flavivirus resistance conferred by the Flv locus and sensitivity to dopamine-controlled hypothermia conferred by a novel locus, Diht. Parallel studies in F1 and F2 heterozygote mice showed that the high sensitivity to hypothermic effect of dopamine (Dih-thigh) is inherited as the Chr5-linked dominant trait. The novel locus, Diht, has been mapped proximal to the Flv locus on a distal part of mouse Chr5 between microsatellite markers D5Mit41 and D5Mit158.

Age Factors↗
PubMed2004

Speed of processing and individual differences in IQ in schizophrenia: General or specific cognitive deficits?

INTRODUCTION: The aim of this study was to re-examine the role of cognitive processing speed in the vulnerability to schizophrenia, using an inspection time (IT) task that does not require a speeded manual response. Since IT consistently correlates with intelligence, the relationship between IT and general intelligence was also explored. METHODS: Patients with schizophrenia were compared with unaffected siblings of schizophrenia patients and healthy controls on a visual IT task. Both speed and variability of IT performance were examined. Current intellectual ability (IQ) was estimated with the Shipley Institute of Living Scale (SILS), which yields separate assessments of verbal and abstraction abilities. RESULTS: Schizophrenia patients produced ITs that were significantly slower and more variable than either unaffected siblings or healthy controls. These results are not related to demographic or clinical variables. A significant negative correlation was obtained between IT and IQ; specifically, longer IT values were associated with abstraction scores only. CONCLUSIONS: These findings confirm that basic cognitive processing efficiency is impaired in patients with schizophrenia. In contrast, ITs in unaffected siblings did not differ from healthy controls, in line with their better IQ test scores. Implications for models of general and specific heritable dimensions in schizophrenia are discussed.

Journal Article↗
PubMed2004

Researching psychiatry in Western Australia.

OBJECTIVE: To provide an overview of the development, approaches and main research projects of the Centre for Clinical Research in Neuropsychiatry (CCRN) in Perth, Western Australia. METHOD: Discursive. RESULTS: Underlying concepts, methods and selected findings of recent research into the neurobiology and epidemiology of schizophrenia, autism and other psychotic disorders are presented. CONCLUSION: CCRN, one of Australia's youngest centres of psychiatric research, has invested fruitfully in research areas such as molecular genetics, neuropsychology, neurophysiology, behavioural pharmacology, diagnostic assessment procedures and record linkage epidemiology.

Adult↗
PubMed2003

Distinguishing between the validity and utility of psychiatric diagnoses.

OBJECTIVE: The meaning of the terms "validity" and "utility" as they apply to psychiatric diagnoses is examined. METHOD: The authors discuss the concepts of validity, utility, and disease; review assumptions that have been made about mental disorders as disease entities; and examine the evidence that mental disorders are separated from one another and from normality by natural boundaries (zones of rarity). RESULTS: Despite historical and recent assumptions to the contrary, there is little evidence that most currently recognized mental disorders are separated by natural boundaries. Researchers are increasingly assuming that variation in symptoms is continuous and are therefore questioning the validity of contemporary classifications. CONCLUSIONS: It is important to distinguish between validity and utility in considering psychiatric diagnoses. Diagnostic categories defined by their syndromes should be regarded as valid only if they have been shown to be discrete entities with natural boundaries that separate them from other disorders. Although most diagnostic concepts have not been shown to be valid in this sense, many possess high utility by virtue of the information about outcome, treatment response, and etiology that they convey. They are therefore invaluable working concepts for clinicians.

Humans↗
PubMed2002

Research methods in psychiatric epidemiology: an overview.

OBJECTIVE: To provide an introduction to the concepts and methods of psychiatric epidemiology for non-specialist readers. METHODS: An overview of concepts and research procedures based on the published literature. CONCLUSION: Psychiatric epidemiology is a key mental health discipline that has adopted and developed a variety of methods and procedures for the study of complex mental disorders. In its future development, psychiatric epidemiology is likely to seek an integration of the conceptual and methodological advances of molecular biology and neuroscience within the population-based and social framework of epidemiology as a basic science of public health.

Epidemiologic Research Design↗
PubMed2002

Antipsychotic use in Australia: the patients' perspective.

OBJECTIVE: To describe patterns of self-reported medication use in a population-based sample of people with psychotic disorders; to establish correlates with clinical variables; to determine perceived side-effect burden; and investigate patient perception of efficacy for different classes of antipsychotic agent. METHODS: Using the Australian Low Prevalence (Psychosis) Study database we analysed patterns of psychotropic medication and examined their clinical correlates. We also determined rates of reported side-effects and perceived benefit or otherwise associated with the different antipsychotic drugs. RESULTS: Of the 1126 persons interviewed, 88.6% were on psychotropic medication; 54.3% were using "typical" antipsychotics (24.8% in depot form), while 8.3% were on clozapine, 13.3% on risperidone, and 8.8% on olanzapine. Around 30% of women, and 20% of men, were on mood stabilizers or antidepressants. Over half of respondents were on more than one agent. Of those on only one agent, nearly 80% reported at least one side-effect; the mean number of side-effects was 3.9 for typical antipsychotics, and 3.3 for atypicals. Atypicals, notably clozapine, tended to be rated by patients as more efficacious than typicals; depot preparations, in particular, tended to be seen as unhelpful, and were associated with a higher side-effect burden. CONCLUSIONS: This study presents an insight into patients' perception of efficacy and side-effects of antipsychotic medications. The findings have implications for clinicians, and can inform treatment options in people with psychotic disorders.

Adolescent↗