A developmental model for similarities and dissimilarities between schizophrenia and bipolar disorder

Meta-analyses of cognitive functioning in euthymic bipolar patients and their first-degree relatives

BACKGROUND

Previous work suggests that impairments in executive function and verbal memory in particular may persist in euthymic bipolar patients and serve as an indicator of genetic risk (endophenotype).

METHOD

A systematic review of the literature was undertaken. Effects sizes were extracted from selected papers and pooled using meta-analytical techniques.

RESULTS

In bipolar patients, large effect sizes (d>0.8) were noted for executive functions (working memory, executive control, fluency) and verbal memory. Medium effect sizes (0.5<d<0.8) were reported for aspects of executive function (concept shifting, executive control), mental speed, visual memory, and sustained attention. Small effect sizes (d<0.5) were found for visuoperception. In first-degree relatives, effect sizes were small (d<0.5), but significantly different from healthy controls for executive function and verbal memory in particular.

CONCLUSIONS

Executive function and verbal memory are candidate bipolar endophenotypes given large deficits in these domains in bipolar patients and small, but intermediate, cognitive impairments in first-degree relatives.

Auditory P300 in patients with bipolar disorder and their unaffected relatives

OBJECTIVES

There is evidence that genetic susceptibility may be shared between bipolar disorder (BD) and schizophrenia, but electrophysiological phenotypes which have been extensively used in studies of genetic susceptibility for schizophrenia remain far less explored in bipolar illness. This study assesses whether auditory P300 latency delays and amplitude reductions, which have been demonstrated in patients with schizophrenia and their unaffected first-degree relatives, are associated with familial liability to psychotic bipolar illness.

METHODS

The P300 auditory evoked potential was obtained using an oddball task from 37 participants with BD who had a history of psychotic symptoms, 38 of their unaffected first-degree relatives and 42 healthy unrelated comparison subjects. Patients and relatives came from families multiply affected with BD or another functional psychotic disorder. P300 amplitude and latency at midline sites were compared between the groups, using linear regression analyses and robust variance estimators for clustered data, including age and gender as covariates.

RESULTS

Bipolar disorder patients with a history of psychosis and their unaffected relatives showed significantly delayed P300 latency at Pz compared to controls. The groups did not differ in P300 amplitude.

CONCLUSIONS

P300 latency delays are associated with both psychotic BD and familial liability for this illness. Sample size limited our ability to test for multimodal distribution of P300 measures among relatives, which might be expected if only a subgroup inherits any deficits. In future it will be of interest to directly compare groups of families with psychotic and non-psychotic forms of BD to explore further the role of psychotic symptoms with regard to P300 measures in the disorder. Our results indicate that delayed P300 latency is a promising candidate endophenotype for psychotic BD, as well as schizophrenia, and may reflect the impact of shared susceptibility genes for both types of psychosis.

Genetic analysis of the gene coding for DARPP-32 (PPP1R1B) in Japanese patients with schizophrenia or bipolar disorder

Several lines of evidence, including genome-wide linkage scans and postmortem brain studies of patients with schizophrenia or bipolar disorder, have suggested that DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, 32 kDa), a key regulatory molecule in the dopaminergic signaling pathway, is involved in these disorders. After evaluating the linkage disequilibrium pattern of the gene encoding DARPP-32 (PPP1R1B; located on 17q12), we conducted association analyses of this gene with schizophrenia and bipolar disorder. Single-marker and haplotypic analyses of four single nucleotide polymorphisms (SNPs; rs879606, rs12601930, rs907094, and rs3764352) in a sample set (subjects with schizophrenia=384, subjects with bipolar disorder=318, control subjects=384) showed that PPP1R1B polymorphisms were not significantly associated with schizophrenia, whereas, even after Bonferroni corrections, significant associations with bipolar disorder were observed for rs12601930 (corrected genotypic p=0.00059) and rs907094 (corrected allelic p=0.040). We, however, could not confirm these results in a second independent sample set (subjects with bipolar disorder=366, control subjects=370). We now believe that the significant association observed with the first sample set was a result of copy number aberrations in the region surrounding these SNPs. Our findings suggest that PPP1R1B SNPs are unlikely to be related to the development of schizophrenia and bipolar disorder in the Japanese population.

AKT1 is associated with schizophrenia across multiple symptom dimensions in the Irish study of high density schizophrenia families

BACKGROUND

The phosphatidylinositol 3-kinase (PI3K)-AKT signal transduction pathway is critical to cell growth and survival. In vitro functional studies indicate that the candidate schizophrenia susceptibility gene DTNBP1 influences AKT signaling to promote neuronal viability. The AKT1 gene has also been implicated in schizophrenia by association studies and decreased protein expression in the brains of schizophrenic patients.

METHODS

The association of DTNBP1 in the Irish Study of High Density Schizophrenia Families (ISHDSF) prompted our investigation of AKT1 for association with disease in this sample. Eight single nucleotide polymorphisms spanning AKT1 were analyzed for association with schizophrenia across four definitions of affection and according to Operational Criteria Checklist of Psychotic Illness (OPCRIT) symptom scales. We examined expression of AKT1 messenger RNA from postmortem brain tissue of schizophrenic, bipolar, and control individuals.

RESULTS

No single marker showed significant association, but the risk haplotype previously found over-transmitted to Caucasian schizophrenic patients was significantly under-transmitted in the ISHDSF (.01 < p < .05), across all OPCRIT symptom dimensions. Exploratory haplotype analysis confirmed association with schizophrenia toward the 5' end of AKT1 (.008 < p < .049, uncorrected). We found significantly decreased RNA levels in prefrontal cortex of schizophrenic individuals, consistent with reduced AKT1 protein levels reported in schizophrenic brain.

CONCLUSIONS

The replication of association of AKT1 gene variants in a further Caucasian family sample adds support for involvement of AKT signaling in schizophrenia, perhaps encompassing a broader clinical phenotype that includes mood dysregulation. We show that AKT signaling might be compromised in schizophrenic and bipolar patients via reduced RNA expression of specific AKT isoforms.

Clinical diagnoses in young offspring from eastern Québec multigenerational families densely affected by schizophrenia or bipolar disorder

OBJECTIVE

The follow-up since 1989 of a large sample of multigenerational families of eastern Québec that are densely affected by schizophrenia (SZ) or bipolar disorder (BP) has permitted to look at the rates of DSM diagnoses in the young offspring of a SZ parent (HRSZ) and of a BP parent (HRBP) who had an extremely loaded family history.

METHOD

The sample (average age of 17.5, SD 4.5) consisted of 54 high-risk offspring (HR) having one parent affected by a DSM-IV SZ or BP. The parents descended from 21 multigenerational families that constitute a quasi-total sample of such kindred in eastern Québec. The HRs were administered a lifetime best estimate DSM-IV diagnosis.

RESULTS

We observed that the rates, the diversity of diagnoses, the high comorbidity, the severity and the age of onset of the clinical diagnoses tended to be similar with those already reported in the offspring of affected parents with a low familial loading. Although the sample size was small, HRSZ and HRBP also tended to show similarities in their clinical status.

CONCLUSION

Overall, taking into account methodological limitations, the observation early in life of some shared characteristics among HRSZ and HRBP in terms of non-psychotic diagnosis may be congruent with the accumulating evidence that several phenotypic features are shared in adulthood by the two major psychoses.

Dermatoglyphic asymmetry and hair whorl patterns in schizophrenic and bipolar patients

Dermatoglyphic quantitative counts, asymmetry between two hands, and hair whorls were assessed in schizophrenic, bipolar and normal samples. Higher dermatoglyphic directional asymmetry and lower fluctuating asymmetry in bipolar patients support their hypernormal asymmetries. An inverse association between hair whorl location and dermatoglyphic asymmetry in schizophrenia may show a higher probability of lateralization problems.

Renner T. Genetische Befunde zu Schizophrenie

Zusammenfassung: Schizophrene Erkrankungen zeichnen sich durch eine sehr heterogene Symptomatik mit übergreifenden Funktionsstörungen verschiedenster kognitiver Bereiche aus. Die vielfältigen Phänotypen werden durch das Zusammenwirken von genetischer Prädisposition und Umwelteinflüssen erklärt. Pathophysiologische Modelle beinhalten die Dopamin-Überschuss- sowie Glutamat-Mangel-Hypothese, die Radikal-Hypothese und die Hypothese entwicklungsbedingter versus degenerativer Genese. Neben den neurobiologischen Erklärungsansätzen geben Kopplungsstudien mit nachfolgenden Feinkartierungen Hinweise auf potentiell an der Pathophysiologie beteiligte Gene. Den wichtigsten Kandidatengenen, wie Dysbindin (DTNBP1), Neuregulin1 (NRG1) oder DISC-1 (disrupted-in schizophrenia-1), werden Einfluss auf die Signalübertragung sowie der Ausbildung und dem Erhalt der Struktur von neuronalen Netzwerken zugeschrieben. Zu ihnen werden zahlreiche weitere Gene gezählt. Insgesamt ist bei der Pathogenese der Schizophrenie von einer multifaktoriellen Entstehung mit der Interaktion von verschiedenen genetischen und neurobiologischen sowie exogenen Komponenten auszugehen.

Diagnostic and sex effects on limbic volumes in early-onset bipolar disorder and schizophrenia

OBJECTIVE

The limbic structures in early-onset schizophrenia-spectrum illness (SZ) and bipolar disorder (BPD) were studied to discern patterns associated with diagnosis and sex.

METHODS

Thirty-five youths with DSM-IV BPD without psychosis, 19 with BPD with psychosis, 20 with SZ, and 29 healthy controls (HC), similar in age (6-17 years) and sex, underwent structured and clinical interviews, neurological examination, and cognitive testing. Structural magnetic resonance images (MRIs) were acquired on a 1.5 Tesla, General Electric Signa Scanner. Differences in subcortical brain volumes, including the amygdala and hippocampus, were evaluated using two-way (diagnosis, sex) univariate analyses covarying for total cerebral volume and age.

RESULTS

Youth with SZ and BPD showed no differences in amygdala and hippocampal volumes. However, boys with SZ had smallest left amygdala and girls with BPD had the smallest left hippocampal volumes. In exploratory analyses, SZ showed reduced thalamic volumes bilaterally and both BPD groups had larger right nucleus accumbens (NA) volumes relative to HC.

CONCLUSION

There were no limbic volumetric differences between BPD and SZ. However, there were diagnosis-by-sex interactions in the amygdala and hippocampus, structures that are rich in sex hormone receptors. In addition, smaller thalamus was associated with SZ while larger right NA volumes were most related to BPD. This study underscores the importance of assessing diagnostic effects and sex effects on the brain in future studies and provides evidence that boys and girls with SZ and BPD may have differential patterns of neuropathology associated with disease expression.

Positional pathway screen of wnt signaling genes in schizophrenia: association with DKK4

BACKGROUND

Wnt signaling has been implicated in schizophrenia from studies of gene expression in patients, from an understanding of the function of reported susceptibility genes and from experimental studies of psychoactive drugs. This diverse evidence suggests that wnt signaling genes, defined as pathway participants, modifiers or targets, are good candidates as susceptibility factors.

METHODS

We performed a combined positional and candidate association screen by identifying known wnt signaling genes in regions linked to schizophrenia. In a staged study we examined over 50 single nucleotide polymorphisms (SNPs) in 28 wnt signaling genes, first in trios of Chinese origin and then in a case-control series from Hong Kong.

RESULTS

In both sets, Dickkopf 4 (DKK4) was associated with schizophrenia - with an odds ratio of 3.9 (p < .01, CI = 1.3-11.1) in the combined sample.

CONCLUSIONS

As DKK family members have previously been found to show altered expression in schizophrenia brain and to bind to neuregulin, this finding suggests that DKK4 may play a role in schizophrenia pathogenesis.

In vivo evidence for early neurodevelopmental anomaly of the anterior cingulate cortex in bipolar disorder

OBJECTIVE

Anterior cingulate cortex (ACC) abnormalities are commonly reported in studies of patients with bipolar disorder (BD), but it is unclear whether these precede or follow illness onset. We investigated the evidence for early neurodevelopmental anomalies in the ACC and adjacent paracingulate cortex (PaC) of BD patients by studying cortical folding patterns of the region.

METHOD

Magnetic resonance images were acquired from 54 BD patients and 116 healthy controls. Cortical folding patterns were assessed by classifying the incidence of the paracingulate sulcus (PCS) and interruptions in the course of the cingulate sulcus (CS).

RESULTS

Patients were significantly less likely to show a PCS bilaterally. There were no differences in the frequency of CS interruptions.

CONCLUSION

The bilateral reduction observed in our patient sample implicates aberrant pre- or peri-natal developmental processes. To our knowledge, this is the first in vivo evidence for early neurodevelopmental anomaly of the ACC/PaC region in BD.

A hierarchical algorithm for MR brain image parcellation

We introduce an algorithm for segmenting brain magnetic resonance (MR) images into anatomical compartments such as the major tissue classes and neuro-anatomical structures of the gray matter. The algorithm is guided by prior information represented within a tree structure. The tree mirrors the hierarchy of anatomical structures and the subtrees correspond to limited segmentation problems. The solution to each problem is estimated via a conventional classifier. Our algorithm can be adapted to a wide range of segmentation problems by modifying the tree structure or replacing the classifier. We evaluate the performance of our new segmentation approach by revisiting a previously published statistical group comparison between first-episode schizophrenia patients, first-episode affective psychosis patients, and comparison subjects. The original study is based on 50 MR volumes in which an expert identified the brain tissue classes as well as the superior temporal gyrus, amygdala, and hippocampus. We generate analogous segmentations using our new method and repeat the statistical group comparison. The results of our analysis are similar to the original findings, except for one structure (the left superior temporal gyrus) in which a trend-level statistical significance (p = 0.07) was observed instead of statistical significance.

Does cannabis use predict the first incidence of mood and anxiety disorders in the adult population?

AIMS

To investigate whether cannabis use predicted the first incidence of mood and anxiety disorders in adults during a 3-year follow-up period.

DESIGN AND PARTICIPANTS

Data were derived from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a prospective study in the adult population of 18-64 years. The analysis was carried out on 3881 people who had no life-time mood disorders and on 3854 people who had no life-time anxiety disorders at baseline.

MEASUREMENTS

Life-time cannabis use and DSM-III-R mood and anxiety disorders, assessed with the Composite International Diagnostic Interview (CIDI).

FINDINGS

After adjustment for strong confounders, any use of cannabis at baseline predicted a modest increase in the risk of a first major depression (odds ratio 1.62; 95% confidence interval 1.06-2.48) and a stronger increase in the risk of a first bipolar disorder (odds ratio 4.98; 95% confidence interval 1.80-13.81). The risk of 'any mood disorder' was elevated for weekly and almost daily users but not for less frequent use patterns. However, dose-response relationships were less clear for major depression and bipolar disorder separately. None of the associations between cannabis use and anxiety disorders remained significant after adjustment for confounders.

CONCLUSIONS

The associations between cannabis use and the first incidence of depression and bipolar disorder, which remained significant after adjustment for strong confounders, warrant research into the underlying mechanisms.

P50 auditory evoked potential suppression in bipolar disorder patients with psychotic features and their unaffected relatives

BACKGROUND

Diminished suppression of the P50 response, a consistent finding in schizophrenia, has also been reported in patients with psychotic bipolar disorder. It is a promising endophenotype for schizophrenia, but its relationship to genetic liability in bipolar disorder is unknown. We therefore assessed whether diminished P50 suppression is associated with familial risk for psychotic bipolar disorder.

METHODS

The P50 response was collected in a conditioning (C)--testing (T) paradigm from 42 outpatients with bipolar 1 disorder who had experienced psychotic symptoms and 44 of their unaffected first-degree relatives, all from families multiply affected with bipolar disorder or another non-organic psychotic disorder; 48 healthy control subjects were also studied. The T/C ratio was compared between the groups, with linear regression analyses and robust variance estimators for clustered data.

RESULTS

Both patients (estimated mean difference in T/C ratio to control subjects, 32, 95% confidence interval [CI] 15-48, p=.001) and unaffected relatives (20, 95% CI 7-32, p=.002) demonstrated higher T/C ratio, thus indicating diminished P50 suppression compared with control subjects.

CONCLUSIONS

To our knowledge, this is the first report of diminished P50 gating in unaffected relatives of psychotic bipolar disorder patients from multiply affected families. Our results suggest that impaired P50 gating is a putative endophenotype for psychotic bipolar disorder and thus might reflect the impact of susceptibility genes across psychosis.

Schizoaffective disorder merges schizophrenia and bipolar disorders as one disease--there is no schizoaffective disorder

PURPOSE OF REVIEW

Schizoaffective disorder was named as a compromise diagnosis in 1933, and remains popular as judged by its place in the International Classification of Diseases and the Diagnostic and Statistical Manual of Mental Disorders, its frequent use in clinical practice, and its extensive discussion in the literature. Some, however, have questioned the validity of schizoaffective disorder as separate from psychotic mood disorder. We examined the literature to assess the rationale for the continuation of schizoaffective disorder as a legitimate diagnostic category.

RECENT FINDINGS

The diagnosis of schizoaffective disorder depends on the disease specificity of the diagnostic criteria for schizophrenia; however, the psychotic symptoms for schizophrenia, traditionally held as specific, can be accounted for by psychotic bipolar. Further, the interrater reliability for diagnosing schizoaffective disorder is very low. A recent and expanding body of comparative evidence from a wide range of clinical and basic science studies, especially genetic, reveals multiple similarities between schizoaffective disorder, schizophrenia and psychotic bipolar.

SUMMARY

Schizoaffective disorder unifies schizophrenia and bipolar, blurring the zones of rarity between them and suggesting that schizoaffective disorder is not a separate, 'bona-fide' disease. Patients diagnosed with schizoaffective disorder likely suffer from a psychotic mood disorder. The diagnosis of schizoaffective disorder, which can result in substandard treatment, should be eliminated from the diagnostic nomenclature.

Biological, life course, and cross-cultural studies all point toward the value of dimensional and developmental ratings in the classification of psychosis

The diagnostic criteria for schizophrenia in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) are based on the premise that it is a discrete illness entity, in particular, distinct from the affective psychoses. This assumption has persisted for more than a century, even though patients with a diagnosis of schizophrenia show a wide diversity of symptoms and outcomes, and no biological or psychological feature has been found to be pathognomonic of the disorder. However, there has been sustained, and indeed growing, criticism of the concept. For example, writing about the diagnosis of schizophrenia more than a decade ago,2 one of Britain's most sophisticated nosological experts, Ian Brockington, enjoined "It is important to loosen the grip which the concept of 'schizophrenia' has on the minds of psychiatrists. Schizophrenia is an idea whose very essence is equivocal, a nosological category without natural boundaries, a barren hypothesis. Such a blurred concept is 'not a valid object of scientific enquiry'."3 Should Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition(DSM-V), persist with the neo-Kraepelinian concept of schizophrenia with all its defects, or should it deconstruct psychosis into its component dimensions? In this article, we will address the question by considering 2 main themes, firstly, the role of culture and ethnicity in the diagnosis of psychosis, and secondly, a life course approach to understanding psychosis. We will then discuss whether more progress would be achieved in DSM-V by abandoning the familiar categorical system and instead moving to a dimensional system which rates both developmental impairment and symptom factor scores. However, we will begin by briefly reviewing the recent history of the classification of the psychoses.

The genetic deconstruction of psychosis

Psychiatric research, including the search for predisposing genes, has tended to proceed under the assumptions that schizophrenia and bipolar disorder, as defined in Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and International Statistical Classification of Diseases, 10th Revision, are discrete disease entities with distinct etiology and pathogenesis and that these disease entities can be identified by current "operational" diagnostic conventions. However, recent findings emerging from genetic studies show increasing evidence for an overlap in genetic susceptibility across the traditional binary classification of psychosis. Moreover, the emerging evidence suggests the possibility of relatively specific relationships between genotype and psychopathology. For example, variation in Disrupted in Schizophrenia 1 (DISC1) and Neuregulin 1 (NRG1) may confer susceptibility to a form of illness with mixed features of schizophrenia and mania. The elucidation of genotype-phenotype relationships is at an early stage, but current findings highlight the need to consider alternative approaches to classification and conceptualization for psychiatric research rather than continuing to rely heavily on the traditional categorical approach. We can expect that, over the coming years, molecular genetics will catalyze a reappraisal of psychiatric nosology as well as contribute in a major way to our understanding of pathophysiology and to the development of improved treatments. However, our understanding of the brain mechanisms that link specific gene actions and products to the subjective experience of psychopathological symptoms is likely to be bridged by employing intermediate (or endo-) phenotypes in the domains such as cognition, neurophysiology, or neuroanatomy rather than relying upon clinical measures alone.

Early identification and high-risk strategies for bipolar disorder

OBJECTIVES

To describe and compare the relative merits of different identification strategies for individuals at risk for bipolar disorder (BPD).

METHODS

Selective review of data that support early identification in BPD, with a particular focus on emerging clinical high-risk strategies.

RESULTS

Early detection of individuals at risk for BPD can utilize genetic, endophenotypic and clinical methods. Most published work focuses on genetic familial endophenotypic risk markers for BPD. However, despite encouraging results, problems with specificity and sensitivity limit the application of these data to early prevention programs. In addition, offspring studies of BPD patients systematically exclude the majority of subjects without a first-degree bipolar relative. On the other hand, emerging work in the clinical-high-risk arena has already produced encouraging results. Although still preliminary, the identification of individuals in subsyndromal or attenuated symptom 'prodromal' stages of BPD seems to be an under-researched area that holds considerable promise deserving increased attention. Required next steps include the development of rating tools for attenuated and subsyndromal manic and depressive symptoms and of prodromal criteria that will allow prodromal symptomatology to be systematically studied in patients with recent-onset bipolar, as well as in prospective population-based phenomenology trials and attenuated symptom-based high-risk studies.

CONCLUSIONS

Given the current limitations of each early identification method, combining clinical, endophenotypic and genetic strategies will increase prediction accuracy. Since reliable biological markers for BPD have not been established and since most patients with BPD lack a first-degree relative with this disorder, clinical high-risk approaches have great potential to inform early identification and intervention programs.

Early infections of Toxoplasma gondii and the later development of schizophrenia

Early exposure to several infectious agents has been associated with the later development of schizophrenia. Two recent studies assessed in utero or early postnatal exposure to Toxoplasma gondii. In one study of 63 individuals, who developed schizophrenia spectrum disorders, maternal sera obtained during pregnancy showed an increased risk (OR 2.61) of having IgG antibodies to T. gondii. In the other study of 71 individuals who developed schizophrenia, sera obtained shortly after birth also showed an increased risk (OR 1.79) of having IgG antibodies to T. gondii. Causal linking mechanisms are at present speculative but include possible direct effects of maternal IgG on the developing central nervous system (CNS) of the offspring. Additional studies are underway.

Phenomenology and diagnosis of bipolar disorder in children, adolescents, and adults: complexities and developmental issues

This review addresses the phenomenology of mania/bipolar disorder from a developmental psychopathology perspective and uses cases with longitudinal information to illustrate major points. Beginning with a summary of the phenomenology of bipolar illness as it occurs in adults, the authors identify diagnostic complexities unique to children and adolescents. These include the challenges of characterizing elation and grandiosity; differentiating mania from comorbid symptoms, rages, sequelae of maltreatment, and typical developmental phenomena; and the unique manifestations of psychosis. We conclude with the observation that a significant difference between early and later onset bipolar disorder is that, in the former, there appears to be a global delay or arrest in the development of appropriate affect regulation; whereas in adult-onset bipolar illness, emotion dysregulation generally presents as an intermittent phenomenon. At this juncture, the study of childhood bipolar illness would benefit from a developmental psychopathology perspective to move beyond the level of cross-sectional symptom description to begin to study individuals over time, focusing on developmental, environmental, genetic, and neurobiological influences on manifest behavior.

Early-onset bipolar disorder: a family treatment perspective

Mood disorder symptoms and their associated functional impairments are hypothesized to come about as the result of the conjoint, interactive influences of genetic, biological, and psychological vulnerabilities, family distress, and life stress at different points of development. We discuss a developmental psychopathology model that delineates pathways to high family conflict and mood exacerbation among early-onset bipolar patients. New data from a treatment development study indicate that adolescent bipolar patients in high expressed emotion families have more symptomatic courses of illness over 2 years than adolescents in low expressed emotion families. Chronic and episodic stressors are also correlated with lack of mood improvement while adolescents are in treatment. Family-focused treatment (FFT) given in conjunction with pharmacotherapy appears to ameliorate the course of bipolar disorder in adults. This treatment has recently been modified to address the developmental presentation of bipolar disorder among adolescents. We present data from an open trial of FFT and pharmacotherapy (N = 20) indicating that bipolar adolescents stabilize in mania, depression, and parent-rated problem behaviors over 2 years. Future research should focus on clarifying the developmental pathways to early-onset bipolar disorder and the role of protective factors and preventative psychosocial interventions in delaying the first onset of the disorder.

Volume, neuron density and total neuron number in five subcortical regions in schizophrenia

Several studies have pointed to alterations in mean volumes, neuron densities and total neuron numbers in the caudate nucleus (CN), putamen, nucleus accumbens (NA), mediodorsal nucleus of the thalamus (MDNT) and lateral nucleus of the amygdala (LNA) in schizophrenia. However, the results of these studies are conflicting and no clear pattern of alterations has yet been established in these subcortical regions, possibly due to differences in quantitative histological methods used as well as differences in the investigated case series. The present study investigates these subcortical regions in both hemispheres of the same post-mortem brains for volume, neuron density and total neuron number with high-precision design-based stereology. The analysed case series consisted of 13 post-mortem brains from male schizophrenic patients [age range: 22-64 years; mean age 51.5 +/- 3.3 years (mean +/- SEM)] and 13 age-matched male controls (age range: 25-65 years; mean age 51.9 +/- 3.1 years). A general linear model multivariate analysis of variance with diagnosis and hemisphere as fixed factors and illness duration (schizophrenic patients) or age (controls), post-mortem interval and fixation time as covariates showed a number of statistically significant alterations in the brains from schizophrenic patients compared with the controls. There was a reduced mean volume of the putamen [-5.0% on the left side (l) and -4.1% on the right side (r)] and the LNA (l: -12.1%, r: -17.6%), and a reduced mean total neuron number in the CN (l: -10.4%, r: -10.2%), putamen (l: -8.1%, r: -11.6%) and the LNA (l: -15.9%, r: -16.2%). These data show a previously unreported, distinct pattern of alterations in mean total neuron numbers in identified subcortical brain regions in a carefully selected sample of brains from schizophrenic patients. The rigorous quantitative analysis of several regions in brains from schizophrenic patients and matched controls is crucial to provide reliable information on the neuropathology of schizophrenia as well as insights about its pathogenesis.

Prenatal, perinatal, and postnatal risk factors in obsessive-compulsive disorder

BACKGROUND

The etiology of obsessive-compulsive disorder (OCD) remains unknown, although it is thought to involve an interaction of genetic and environmental factors. This study aimed to identify prenatal, perinatal, and postnatal risk factors in OCD.

METHODS

We compared retrospectively 68 OCD patients to 70 control subjects based on responses given on a standardized questionnaire. The questionnaire was designed to evaluate environmental factors, with a special focus on gestation, labor, birth, and early infancy aspects.

RESULTS

The group of OCD patients had risk factors with greater frequency than the control group. Notable among the significant findings (p < or = 0.001) were edema of the hands, feet, or face and excessive weight gain during gestation; hyperemesis gravidarum; prolonged labor; preterm birth; and jaundice. When socioeconomic class was used as a covariable in the logistic regression analysis, prolonged labor and edema during pregnancy remained statistically significant.

CONCLUSIONS

Some early risk factors may be associated with the expression of OCD later in life such as edema during pregnancy and prolonged labor. If our findings are confirmed in future studies, greater attention should be given to such factors in predisposed individuals, especially in prenatal care and delivery.

Vernier threshold and the parallel visual pathways in bipolar disorder: a follow-up study

Magnocellular (M) and parvocellular (P) visual pathways participate in the processing of low contrast and colors of objects, respectively. The aim of this study was to investigate M and P pathway functions in bipolar disorder during a depressive episode and after the amelioration of symptoms. Participants (17 patients with type I bipolar disorder and 20 matched healthy controls) received two vernier tasks. During the M pathway test, stimuli were dots with low luminance-contrast (5%), whereas during the P pathway test, isoluminant blue dots were presented against a yellow background. Participants were asked to detect the direction of the horizontal displacement of the dots (left or right). The assessment was performed during a depressive state and during a clinically improved state after 2 months. During the depressive state, the patients showed significantly impaired M and P pathway functions, whereas during the clinically improved state, their performance was better and was statistically indistinguishable from that of the controls. In conclusion, M and P pathways are impaired in depressed bipolar patients. This deficit is ameliorated along with clinical improvement. Further studies are necessary to separately assess cortical and precortical stages of information-processing, and to exclude the possibility of general motivational and attentional impairments.

Dimensions and the psychosis phenotype

In this paper, we discuss the conceptual background for including a dimensional component to the DSM V diagnoses for psychoses. We review the evidence for a continuous distribution of psychosis like symptoms in the general population and summarise the research validating the clinical usefulness of psychopathological dimensions. We conclude that diagnostic models using both categorical and dimensional representations of psychosis have better predictive validity than either model independently. Dimensions do not appear to be diagnosis specific so a flexible scoring of dimensions across all psychotic and major affective disorders may be potentially more informative than a system where categorical diagnoses are kept artificially dimension-specific.

Cannabis use and expression of mania in the general population

BACKGROUND

Cannabis use is common in patients with bipolar disorder, however little is known about cannabis as a risk factor for mania. In order to investigate the association between exposure to cannabis and subsequent development of manic symptoms whilst controlling for psychotic symptoms, a longitudinal population-based study was carried out.

METHODS

4815 individuals aged 18 to 64 years were interviewed using the Composite International Diagnostic Interview at baseline, 1 year follow up and 3 year follow up, including assessment of substance use, manic symptoms and psychotic symptoms.

RESULTS

Use of cannabis at baseline increased the risk for manic symptoms during follow-up (adjusted OR 2.70, 95% CI: 1.54, 4.75), adjusted for age, sex, educational level, ethnicity, single marital status, neuroticism, use of other drugs, use of alcohol, depressive symptoms and manic symptoms at baseline. The association between cannabis use and mania was independent of the prevalence and the incidence of psychotic symptoms. There was no evidence for reverse causality, as manic symptoms at baseline did not predict the onset of cannabis use during follow-up (OR = 0.35, 95% CI: 0.03, 3.49).

LIMITATIONS

As 3 years is a relative short period of follow-up, long-term effects of cannabis use on mania outcomes could not be detected.

CONCLUSION

The results suggest that cannabis use may affect population expression of manic symptoms (and subsequent risk to develop bipolar disorder [Regeer, E.J., Krabbendam, L., R, DE Graaf, Ten Have, M., Nolen, W.A., Van Os, J., 2006. A prospective study of the transition rates of subthreshold (hypo)mania and depression in the general population. Psychol Med, 1-9.]). These findings may not be due to the emergence of psychotic symptoms or the effects of self-medication.

Les anomalies structurales observées en imagerie cérébrale dans le trouble bipolaire

The number of structural neuroimaging studies of bipolar disorder have increased during recent years, expanding the literature on the nature of cerebral abnormalities underlying this disorder. The purpose of this paper is to provide a selective review on the main issues concerning this literature. Consistent findings are higher rate of periventricular and deep subcortical white matter hyperintensites seen on MRI. Although there is strong evidence for links between hyper-intense lesions and age or cardio-vascular risk factors, some authors have observed the presence of these abnormalities early in the course of the illness. There are also frequent reports on ventricular enlargement, which has been described as mild and predominant in the right lateral ventricle. Total cerebral volume appears to be preserved. Whereas changes in total grey matter volume are uncertain, evidence suggests that reduced white matter volume reflects genetic factors predisposing to the disorder. Recent studies have reported volume changes in several cortical areas including the subgenual cingular, frontal and temporal cortices. Additionally, a number of reports described morphometric abnormalities in various subcortical structures, such as amygdala, basal ganglia and thalamus. Part of the variability in the morphometric abnormalities might be attributable to differences in clinical status and demographic characteristics of patient groups. Despite some inconsistencies across the studies, it emerges that abnormalities are asymmetrically distributed throughout the two cerebral hemispheres. When increase in volume is reported, it is preferentially localised in the left cerebral hemi-sphere and more specifically in prefrontal and temporal cortices and in amygdala. By contrast, when structural abnormalities concern the right cerebral hemisphere, they are identified as deficits. These latter results are in direct line with those of studies of mania following brain injuries, which report that these secondary mania result mainly from right cerebral lesions. It is also important to notice that most of the abnormalities concern both the cortical and subcortical level, ie frontal, striatal, thalamic and limbic regions. These abnormalities highlight the role in the pathophysiology of bipolar disorder of the loops involved in emotional information processing. The particular role of fronto-limbic loops in the phenomenology of bipolar disorder have been emphasised by recent data from functional neuroimaging studies.

Family-based association study between G72/G30 genetic polymorphism and schizophrenia

Genetic variations in G72/G30 have been reported to be associated with schizophrenia and bipolar disorders in several case-control studies. This gene is located in a genomic region known to contain susceptibility genes for schizophrenia. As case-control studies carry an increased risk of confounding through population stratification, we investigate whether the rs947267 (A/C) polymorphism is associated with schizophrenia in a family-based association study. This polymorphism is located within the G72/G30 gene and has been previously associated with bipolar disorders. The sample consisted of a total of 216 Chinese families that included an affected offspring and parents. Transmission disequilibrium analysis revealed a significant association between the G72/G30 rs947267 polymorphism and schizophrenia (P=0.016), with the A allele more commonly transmitted to patients. Further analysis stratified by sex showed that the A allele was significantly more overtransmitted than nontransmitted in the trios of male probands (P=0.031), but not in the trios of female probands. Our family-based association study supports the suggestion that the G72/G30 gene may be implicated in susceptibility to schizophrenia and there may be an interaction between this gene and sex in the pathogenesis of schizophrenia.

The genetics and biology of DISC1--an emerging role in psychosis and cognition

In the developing field of biological psychiatry, DISC1 stands out by virtue of there being credible evidence, both genetic and biological, for a role in determining susceptibility to schizophrenia and related disorders. We highlight the methodologic paradigm that led to identification of DISC1 and review the supporting genetic and biological evidence. The original finding of DISC1 as a gene disrupted by a balanced translocation on chromosome 1q42 that segregates with schizophrenia, bipolar disorder, and recurrent major depression has sparked a number of confirmatory linkage and association studies. These indicate that DISC1 is a generalizable genetic risk factor for psychiatric illness that also influences cognition in healthy subjects. DISC1 has also been shown to interact with a number of proteins with neurobiological pedigrees, including Ndel1 (NUDEL), a key regulator of neuronal migration with endo-oligopeptidase activity, and PDE4B, a phosphodiesterase that is critical for cyclic adenosine monophosphate signaling and that is directly linked to learning, memory, and mood. Both are potential "drug" targets. DISC1 has thus emerged as a key molecular player in the etiology of major mental illness and in normal brain processes.

Critical appraisal of DNA microarrays in psychiatric genomics

Transcriptome profiling using DNA microarrays are data-driven approaches with the potential to uncover unanticipated relationships between gene expression alterations and psychiatric disorders. Studies to date have yielded both convergent and divergent findings. Differences may be explained, at least in part, by the use of a variety of microarray platforms and analytical approaches. Consistent findings across studies suggest, however, that important relationships may exist between altered gene expression and genetic susceptibility to psychiatric disorders. For example, GAD67, RGS4, DTNBP1, NRG1, and GABRAB2 show expression alterations in the postmortem brain of subjects with schizophrenia, and these genes have been also implicated as putative, heritable schizophrenia susceptibility genes. Thus, we propose that for some genes, altered expression in the postmortem human brain may have a dual origin: polymorphisms in the candidate genes themselves or upstream genetic-environmental factors that converge to alter their expression level. We hypothesize that certain gene products, which function as "molecular hubs," commonly show altered expression in psychiatric disorders and confer genetic susceptibility for one or more diseases. Microarray gene expression studies are ideally suited to reveal these putative disease-associated molecular hubs and to identify promising candidates for genetic association studies.

Association of 677C>T polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene with bipolar disorder and schizophrenia

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphism 677C>T has been shown to be a risk factor for psychiatric disorders. We investigated the genotype and allelic frequencies of MTHFR 677C>T polymorphism in the group of patients with bipolar disorder type I (BDI) (n=200) and schizophrenia (n=200), and in the control group (n=300). Odds ratio (OR) for patients with BD and schizophrenia with 677T allele was 1.988 ((95% CI=1.370-2.883); P=0.0003 (P=0.0006 after Bonferroni correction)) and 1.796 ((95% CI=1.237-2.609); P=0.0020 (P=0.0040 after Bonferroni correction)), respectively. The stratification of patients based on gender revealed significant association of 677T allele with male patients with BDI and schizophrenia (OR=2.393; 95% CI=1.429-4.006; P=0.0008 and OR=2.036; 95% CI=1.207-3.433; P=0.0073, respectively). This finding indicates possible association of BD and schizophrenia with the 1p36.3 MTHFR locus.

Urbanicity during upbringing and bipolar affective disorders in Denmark

BACKGROUND

It has been suggested that known or suspected risk factors for schizophrenia may also be of importance for other psychoses, but the empirical evidence regarding this is limited. Urbanicity of place of birth and during upbringing has been shown to be related to the risk of schizophrenia. Few studies of urbanicity in relation to bipolar affective disorder exist.

OBJECTIVE

To investigate the potential association between urbanicity at birth and during upbringing and the risk of bipolar affective disorder.

METHOD

Using data from the Danish Civil Registration System, we established a population-based cohort of 2.04 million people born in Denmark during 1956-1986, which included information on place of residence during upbringing. Bipolar affective disorder in cohort members was identified by linkage with the Danish Psychiatric Central Register.

RESULTS

Overall, 2232 people developed bipolar affective disorder during 1971-2001. We found evidence of an increased risk associated with residence in the provincial city; individuals, who at the 15th birthday lived in the provincial city, had a risk of 1.23 (1.08-1.41). This increased risk was explained solely by an increased risk associated with residence in Aarhus; at the 15th birthday, people residing in Aarhus - the largest of the three Danish provincial cities - had a 1.83 (1.56-2.14) increased risk of bipolar affective disorder (p < 0.001). Urbanicity during upbringing (p = 0.13) had no significant effects on the risk of bipolar affective disorder.

CONCLUSIONS

We found no evidence of a dose-response relationship between urbanicity at birth (and during upbringing) and the risk of bipolar affective disorders in Denmark, but found some evidence that the diagnostic practices used in Aarhus differed from the rest of Denmark.

Gene regulation by hypoxia and the neurodevelopmental origin of schizophrenia

Neurodevelopmental changes may underlie the brain dysfunction seen in schizophrenia. While advances have been made in our understanding of the genetics of schizophrenia, little is known about how non-genetic factors interact with genes for schizophrenia. The present analysis of genes potentially associated with schizophrenia is based on the observation that hypoxia prevails in the embryonic and fetal brain, and that interactions between neuronal genes, molecular regulators of hypoxia, such as hypoxia-inducible factor 1 (HIF-1), and intrinsic hypoxia occur in the developing brain and may create the conditions for complex changes in neurodevelopment. Consequently, we searched the literature for currently hypothesized candidate genes for susceptibility to schizophrenia that may be subject to ischemia-hypoxia regulation and/or associated with vascular expression. Genes were considered when at least two independent reports of a significant association with schizophrenia had appeared in the literature. The analysis showed that more than 50% of these genes, particularly AKT1, BDNF, CAPON, CCKAR, CHRNA7, CNR1, COMT, DNTBP1, GAD1, GRM3, IL10, MLC1, NOTCH4, NRG1, NR4A2/NURR1, PRODH, RELN, RGS4, RTN4/NOGO and TNF, are subject to regulation by hypoxia and/or are expressed in the vasculature. Future studies of genes proposed as candidates for susceptibility to schizophrenia should include their possible regulation by physiological or pathological hypoxia during development as well as their potential role in cerebral vascular function.

Emotional processing in schizophrenia

INTRODUCTION

Persons with schizophrenia have impaired emotional processing, involving experience, expression, and recognition of emotions.

METHODS

This article reviews the historical descriptions and more recent work on emotion processing in schizophrenia.

RESULTS

Although abilities of emotional processing relate directly to interpersonal communication and psychosocial functioning, methodological issues exist in the current body of studies and resultant knowledge, which limit translation to novel treatment options.

CONCLUSIONS

Further improvement in emotion processing in persons with stable schizophrenia are unlikely to result from conventional pharmacotherapy of psychosis. New treatment modalities and behavioural interventions offer possible improvements in quality of life and psychosocial functioning.

Generalized and specific neurocognitive deficits in prodromal schizophrenia

BACKGROUND

Neurocognitive deficits are considered to be central to the pathophysiology of schizophrenia, and the neurodevelopmental model suggests that such deficits precede full-blown psychosis. The present study examined performance on a broad neuropsychological battery of young subjects considered to be at clinical high risk for schizophrenia, who were subsequently followed to determine clinical outcome.

METHODS

Subjects were 38 clinical high-risk patients (58% male patients; mean age = 16.5) and 39 sex- and age-matched healthy control subjects. At baseline, all high-risk patients had attenuated (subpsychotic) schizophrenialike positive symptoms. Clinical follow-up data of at least 6 months duration was available on 33 patients, of whom 12 developed nonaffective psychotic disorders.

RESULTS

At baseline, clinical high-risk patients had significantly impaired global cognitive performance relative to control subjects and to estimates of their own prior intellectual functioning. Measures of verbal memory and executive functioning/working memory showed significantly greater impairments; visuospatial functioning was relatively spared. Prodromal patients who later developed psychosis had significantly lower verbal memory scores at baseline compared with patients who remained nonpsychotic.

CONCLUSIONS

Verbal memory deficits may be an important risk marker for the development of schizophrenia-spectrum psychotic disorders, possibly indicating the presence of a prefrontal-hippocampal neurodevelopmental abnormality. Generalized neurocognitive impairment may be a nonspecific vulnerability marker.

Developing therapeutics for schizophrenia and other psychotic disorders

Although the second-generation or atypical antipsychotic drugs have been breakthrough medicines for the treatment of schizophrenia and other psychotic conditions, cognitive dysfunction and to some extent negative symptoms of the disease continue to be the main cause of poor vocational status of the patients. Thus, the majority of investigational drug development efforts today target these unmet medical needs. This review postulates that the field of schizophrenia research has advanced sufficiently to develop biochemical hypotheses of the etiopathology of the disease and target the same for revolutionary disease modifying therapy. This postulate is based on recent studies that have begun to provide a testable etiopathology model that integrates interactions between genetic vulnerability factors, neurodevelopmental anomalies, and neurotransmitter systems. This review begins with a brief overview of the nosology and etiopathology of schizophrenia and related psychotic disorders to establish a context for subsequent detailed discussions on drug discovery and development for psychotic disorders. Particular emphasis is placed on recent advances in genetic association studies of schizophrenia and how this can be integrated with evidence supporting neurodevelopmental abnormalities associated with the disease to generate a testable model of the disease etiopathology. An in-depth review of the plethora of new targets and approaches targeting the unmet medical need in the treatment of schizophrenia exemplify the challenges and opportunities in this area. We end the review by offering an approach based on emerging genetic, clinical, and neurobiological studies to discover and validate novel drug targets that could be classified as disease modifying approaches.

Continuities and discontinuities in psychopathology between childhood and adult life

The possible mechanisms involved in continuities and discontinuities in psychopathology between childhood and adult life are considered in relation to the findings from systematic, prospective, long-term longitudinal studies. Findings on schizophrenia, neurodevelopmental disorders, emotional disturbances, antisocial behaviour and substance abuse are used as conditions illustrating the key issues. The overarching themes are then discussed in relation to heterotypic continuity and psychopathologic progression, early age at onset and a range of possible mediating mechanisms - including genetic mediation, 'kindling' effects, environmental influences, coping mechanisms and cognitive processing of experiences. Some of the key research challenges that remain concern the testing of competing hypotheses on mediating processes, the changes involved in adolescence, the transition from prodromal phase to overt schizophrenia and the emergence of adolescent-limited antisocial behaviour. Greater use needs to be made of genetic research strategies and of the testing of possible cognitive processing mediation effects.

Gene-environment interplay and psychopathology: multiple varieties but real effects

Gene-environment interplay is a general term that covers several divergent concepts with different meanings and different implications. In this review, we evaluate research evidence on four varieties of gene-environment interplay. First, we consider epigenetic mechanisms by which environmental influences alter the effects of genes. Second, we focus on variations in heritability according to environmental circumstances. Third, we discuss what is known about gene-environment correlations. Finally, we assess concepts and findings on the interaction between specific identified genes and specific measured environmental risks. In order to provide an understanding of what may be involved in gene-environment interplay, we begin our presentation with a brief historical review of prevailing views about the role of genetic and environmental factors in the causation of mental disorders, and we provide a simplified account of some of the key features of how genes 'work'.

Development of visual motion perception in children of patients with schizophrenia and bipolar disorder: a follow-up study

The "dorsal-stream vulnerability" hypothesis claims that motion-sensitive areas in the dorsal occipito-parietal visual system are vulnerable to genetic and environmental factors which affect brain maturation and development. The aim of this study was to investigate the possibility that developmental anomalies of directional motion perception can be detected in children of mothers with schizophrenia and bipolar disorder. Motion and form coherence thresholds were measured in 36 children of mothers with schizophrenia, 28 children of mothers with bipolar disorder, and 30 children with negative family history at 7, 8-9, and 10-11 years of age. These tasks require the detection of direction of coherently moving dots embedded among randomly oscillating dots (motion task) and the detection of tangentially oriented line-segments embedded among randomly oriented segments (form task). Results revealed that the rate of development in the motion task was less pronounced in children of mothers with schizophrenia than that in children of mothers with bipolar disorder and in age-matched controls. The development of form perception was spared. Children of mothers with bipolar disorder showed an intact development in both motion and form perception tasks. These results suggest that the progressive developmental abnormality of motion-sensitive visual areas may be a characteristic feature of schizophrenia-vulnerability.

The psychopathology and treatment of bipolar disorder

In this chapter we review research on the diagnosis, course, etiology, and pharmacological and psychosocial treatment of bipolar disorder (BD). BD is a highly recurrent and severe illness, with high rates of suicidality and functional impairment. The disorder is heritable and appears to share susceptibility genes with schizophrenia. It is characterized by dysregulation in the dopamine and serotonin systems and by pathology in the brain systems involved in regulating emotion. Psychosocial stressors, notably life events and familial expressed emotion, significantly influence the course of the illness in the context of these vulnerabilities. Findings of randomized clinical trials indicate that psychosocial interventions enhance long-term outcomes when added to pharmacotherapy. Much remains to be clarified about the interactive contributions of genetic, neurobiological, and psychosocial factors to the course of the disorder, and the moderators and mediators of treatment effects.

Genes for schizophrenia and bipolar disorder? Implications for psychiatric nosology

It has been conventional for psychiatric research, including the search for predisposing genes, to proceed under the assumption that schizophrenia and bipolar disorder are separate disease entities with different underlying etiologies. These represent Emil Kraepelin's traditional dichotomous classification of the so-called "functional" psychoses and form the basis of modern diagnostic practice. However, findings emerging from many fields of psychiatric research do not fit well with this model. In particular, the pattern of findings emerging from genetic studies shows increasing evidence for an overlap in genetic susceptibility across the traditional classification categories-including association findings at DAOA(G72), DTNBP1 (dysbindin), COMT, BDNF, DISC1, and NRG1. The emerging evidence suggests the possibility of relatively specific relationships between genotype and psychopathology. For example, DISC1 and NRG1 may confer susceptibility to a form of illness with mixed features of schizophrenia and mania. The elucidation of genotype-phenotype relationships is at an early stage, but current findings highlight the need to consider alternative approaches to classification and conceptualization for psychiatric research rather than continuing to rely heavily on the traditional Kraepelinian dichotomy. As psychosis susceptibility genes are identified and characterized over the next few years, this will have a major impact on our understanding of disease pathophysiology and will lead to changes in classification and the clinical practice of psychiatry.

Cognitive functioning in patients with schizophrenia and bipolar disorder: a quantitative review

OBJECTIVE

Evidence suggests that cognitive functioning in bipolar disorder may be impaired even in euthymic states, but it is unclear if the pattern of deficits is similar to the deficits found in schizophrenia. The aim of this study was to review quantitatively the studies on cognitive performance in schizophrenia and bipolar disorder.

METHODS

Articles for consideration were identified through a literature search in MEDLINE and PsycLIT in the period between 1985 and October 2004, using the keywords "schizophrenia" combined with "bipolar disorder", or "manic-depress*" or "manic" combined with "cogniti*" or "neuropsycholog*". Thirty-one studies were included that: i) evaluated cognitive performance using standardized and reliable neuropsychological testing procedures; ii) compared adult patients with schizophrenia and with bipolar disorder; iii) reported test scores of both patient groups, or exact p-values, t-values, or F-values; and iv) were published as an original article in a peer-reviewed English language journal.

RESULTS

Meta-analyses of all studies indicated that patients with bipolar disorder generally perform better than patients with schizophrenia, but the distribution of effect sizes showed substantial heterogeneity. Results based on a more homogeneous subset of studies that matched patient groups on clinical and demographic characteristics pointed in the same direction, with effect sizes in the moderate range.

CONCLUSIONS

Patients with bipolar disorder show better cognitive performance than patients with schizophrenia, even when matched for clinical and demographic characteristics.

What causes the onset of psychosis?

It has become increasingly clear that the simple neurodevelopmental model fails to explain many aspects of schizophrenia including the timing of the onset, and the nature of the abnormal perceptions. Furthermore, we do not know why some members of the general population have anomalous experiences but remain well, while others enter the prodrome of psychosis, and a minority progress to frank schizophrenia. We suggest that genes or developmental damage result in individuals vulnerable to dopamine deregulation. In contemporary society, this is often compounded by abuse of drugs such as amphetamines and cannabis, which then propel the individual into a state of dopamine-induced misinterpretation of the environment. Certain types of social adversity such as migration and social isolation, as well as affective change can also contribute to this. Thereafter, biased cognitive appraisal processes result in delusional interpretation of the abnormal perceptual experiences. Thus, a plausible model of the onset of psychosis needs to draw not only on neuroscience, but also on the insights of social psychiatry and cognitive psychology.

Cognitive performance in presumed obligate carriers for psychosis

We report cognitive performance of a group of individuals who are likely to have transmitted liability to psychosis to their offspring. Out of 230 relatives of patients with psychosis, 27 met our criteria for a presumed obligate carrier, that is a non-psychotic individual who had a parent or a sibling as well as an offspring with psychosis. The presumed obligate carriers showed impairments in verbal memory and in visuospatial manipulations, suggesting that these individuals transmit vulnerability for psychosis to their offspring in terms of a disability to recall verbal information and an impaired capacity to perceive spatial relations.

Dimensions of premorbid functioning in schizophrenia: a review of neuromotor, cognitive, social, and behavioral domains

After a brief discussion of methods for studying the premorbid period in schizophrenia, the authors review relevant experimental literature to assess the validity of current theories. A critical review is provided that includes representative empirical investigations on premorbid functioning in schizophrenia in the domains of neuromotor, intellectual, academic, cognitive, social, emotional, and behavioral functioning. Limitations of past research, such as lack of specificity to schizophrenia populations, high incidences of false positives, questionable definitions of the premorbid period, inconsistent measures of premorbid functioning, and problems with the current method of DSM classification are discussed. Alternative approaches to studying early functioning in schizophrenia are highlighted.

Prospective study of adolescents with subsyndromal psychosis: characteristics and outcome

OBJECTIVE

The aim of this study was to examine the characteristics and outcome of adolescents with psychotic disorder not otherwise specified (PsyNOS) and brief psychotic disorder (BrPsy), two neglected subsyndromal diagnostic entities.

METHODS

As part of an ongoing, naturalistic study investigating adolescents considered to be prodromal for schizophrenia, 29 youngsters (mean age, 16.2 +/- 2.7 years) with PsyNOS or BrPsy were identified as theoretically at highest risk for schizophrenia and followed for over 6 (mean, 22.8 +/- 19.4) months.

RESULTS

Contrary to our expectations, only 7 of the 26 individuals (27.0%) with follow-up data developed schizophrenia or schizoaffective disorder, and only 2 subjects (7.7%) retained their diagnosis of BrPsy/PsyNOS. The most frequent other diagnoses at follow-up were mood disorders (34.6%), personality disorders (11.5%), and obsessive-compulsive disorder (7.7%). Regarding severity of outcome, 38.5% of the patients progressed to a syndromal psychotic disorder, 23.1% continued to have attenuated positive symptoms, and 38.4% improved to having attenuated negative symptoms only, or no positive or negative symptoms. BrPsy was associated with lower maximum levels of negative symptoms (p = 0.02) and higher likelihood of symptom remission (p = 0.02).

CONCLUSIONS

This study indicates that psychotic symptoms not fulfilling criteria for schizophrenia or a psychotic mood disorder are unreliable predictors of a syndromal psychotic disorder outcome at 2 years. Long-term studies of PsyNOS and BrPsy are needed to clarify where these disorders fall in the developmental course of schizophrenia.